¹ I am at present preparing a series of studies on medieval monastic buildings in Rome and I have found such distinctions useful in analysing the buildings.

² Lugli, G., La tecnica edilizia romana con particolare riguardo a Roma e Lazio, Rome 1957Google Scholar, surveys Ancient Roman methods of construction. Ghetti, B. M. Apollonij, de Angelis d'Ossat, G., Ferrua, A. and Venanzi, C., ‘Le strutture murarie delle chiese paleocristiane di Roma’, RAC XXI (1944/1945) 223 ff.Google Scholar, discusses early Christian masonry. Venanzi, C., Caratteri costruttivi dei monumenti, I. Strutture murarie a Roma e nel Lazio, Spoleto, 1953Google Scholar, goes from early Christian times till the fifteenth century. G. Bertelli, A. Guiglia Guidobaldi and P. Rovigatti Spagnoletti Zeuli, ‘Strutture murarie degli edifici religiosi di Roma dal VI al IX secolo’, and Avagnina, M. E., Garibaldi, V. and Salterini, C., ‘Strutture murarie degli edifici religiosi di Roma nel XII secolo’, Rivista dell'Istituto Nazionale d'Archeologia e Storia dell'Arte, XXIII–XXIV (1976–1977) 95 ff. and 173 ffGoogle Scholar. give details of masonry types in Roman churches of the sixth to ninth century (in the first article) and of the twelfth century (in the second). In future we shall refer to these studies as Strutture Murarie I and Strutture Murarie II. Heres, T. L., Paries, Amsterdam, 1982Google Scholar, proposes a dating system for masonry in Rome and Ostia, A.D. 235–600.

Several works, although not confined to the study of masonry, are a rich mine of information on this subject. Chief among these is Krautheimer, R., Corpus Basilicarum Christianarum Romae, Vatican City, 1937–1977, 5 vols.Google Scholar, hereafter referred to as Krautheimer, Corpus. Giovenale, G. B., La basilica di S. Maria in Cosmedin, Rome, 1927Google Scholar, and Malmstrom, R. E., S. Maria in Aracoeli at Rome, unpublished Ph. D. thesis, New York University, 1973, 27 ff.Google Scholar, 39 f. 132, n. 303 give data pertaining to different types of masonry in use in Rome in the Middle Ages.

³ Strutture Murarie II.

⁴ I have re-arranged their churches in alphabetical order, for convenient reference. I have indicated in the third column of Table II whether they are in my opinion firmly or approximately dated, or undated by documentary evidence. When only parts of the building are medieval I have noted that too.

Since in Table I I have consistently used a modulus of 5 courses of brick or tufa and mortar, I have quoted only the 5 × 5 modulus given in Strutture Murarie II in Table II, leaving out the 3 × 3 modulus, which the authors usually give as well.

⁵ In the notes, we shall refer to the churches and masonry types studied by Avagnina et al. according to their numbers in Table II, to facilitate convenient cross-reference.

⁶ For ‘tufa’, read tufa (yellowish in colour) or peperino (darker and more green in colour); both are local stone in Rome and both were widely used, alone or together, in medieval masonry.

⁷ The authors of Strutture Murarie II like to refer to pure brickwork as opus testaceum; elsewhere it is often called opus latericium, as e.g. in T. L. Heres, op. cit., 12 and passim.

⁸ I follow Krautheimer in using this term, see Krautheimer, Corpus, passim, despite objections by some scholars, such as C. Venanzi, op. cit., 18 f. and Strutture Murarie II, passim, who prefer to call this masonry opera listata or opus mixtum. T. L. Heres, op. cit., 13 and passim prefers the term opus vittatum for this kind of masonry.

⁹ For this term, Krautheimer, R., Rome: Profile of a City, 312–1308, Princeton, 1980, 203, 293Google Scholar and Krautheimer, Corpus, passim.

¹⁰ For example, by C. Venanzi, op. cit., 35 ff., and Strutture Murarie II, where falsa cortina is defined (p. 246) as ‘… una muratura uniforme, in cui i mattoni ed i giunti di malta non si distinguono, ricoperti come sono da un sottile strato di malta o di intonaco, il cosidetto latte di malta …’, but elsewhere the authors seem to mean mortar marked with stilatura, incised horizontal lines.

¹¹ For example, by Giovenale, Krautheimer and Malmstrom, in the works cited in note 2, and frequently in Strutture Murarie II, see previous note.

¹² Table II, IX and XIX; Krautheimer, , Corpus, II, 1959, 41 and 43Google Scholar. In the case of their entry on S. Lorenzo f.l.m. (Table II, IX) Avagnina et al. claim to have seen finta cortina in the cloister. I have observed it in the thirteenth century nave and narthex of the church, as did Krautheimer, op. cit., loc. cit., but nowhere in the monastery.

¹³ See the study by Guidobaldi, F., ‘Il complesso archeologico di S. Clemente’, in San Clemente Miscellany II: Art and Archaeology, ed. Dempsey, L., , O. P., Rome, 1978, 215 ffGoogle Scholar.

¹⁴ Krautheimer, Corpus, passim; see also Strutture Murarie I, passim; Heres, op. cit., passim. For relative dimensions, see below and note 81.

¹⁵ ‘… ecclesiam sanctorum Quatuor Coronatorum quae tempore Roberti Guiscardi Salernitani principis destructa erat, a fundamentis refecit atque consecravit anno pontificatus sui X° VII° mense ian, die XX°’, Life of Paschal II, LP, II, 305Google Scholar. Paschal in a Bull issued on May 24, 1116, says ‘Nostris sane temporibus sanctorum Quatuor Coronatorum ecclesiam tituli nomine insignem igne consumptam novimus … ecclesiam licet minoribus spatiis reparare … curavimus’, quoted by Muñoz, A., Il restauro della chiesa e del chiostro dei SS. Quattro Coronati, Rome, 1914, 4 fGoogle Scholar. and Krautheimer, , Corpus, IV, 1970, 3 fGoogle Scholar.

We follow Krautheimer, , Corpus, IV, 1970, 1 ffGoogle Scholar. in taking this documentary evidence for dating these two building phases. In Strutture Murarie II, 180 (Table II, XVII) C. Salterini considered the possibility of a first Romanesque rebuilding phase prior to 1084, but, to my mind, gave no convincing evidence in support of her theory. Krautheimer, op. cit., loc. cit., has clearly distinguished the two later medieval building campaigns.

¹⁶ My description agrees with that in Strutture Murarie II, Table II, XVII, Phase I.

¹⁷ Table II, XVII gives two different 5 × 5 moduli for this building phase, one of which, the second, closely resembles that which I measured. The first, said to be taken in the blocking of the phase I colonnade, is, I think, taken from the outer wall of the Chapel of S. Silvestro (1246), built into the phase I colonnade, but in the courtyard outside the phase II church and hence not pertaining to it. (This is a case where I believe C. Salterini has not distinguished the extent of the twelfth century building phase correctly).

¹⁸ Inscription on the altar, Giovenale, op. cit., 63 and note 9; Forcella, V., Iscrizioni delle chiese e d'altri edifici di Roma dal secolo XI fino ai giorṇi nostri, Rome, 1864–1888 (henceforth referred to as Forcella, Iscrizioni), IV, p. 305Google Scholar, no. 742; Krautheimer, , Corpus, II, 1959, 280Google Scholar.

¹⁹ Table II, XII; it is not clear why only part of the narthex was considered twelfth century, why only one brick was measured, or where the dimensions were taken. Only one reading of the 5 × 5 modulus, c. 35 cm., is given, which is not an adequate record. Although I occasionally found such a high modulus, the average was closer to 30–31 cm. Thus, I do not believe the figure given in Strutture Murarie II is representative of the twelfth-century brickwork in S. Maria in Cosmedin.

²⁰ Inscription now in the choir of the church and next to the sacristy door; transcribed by Ghetti, B. M. Apollonij, S. Crisogono (Le Chiese di Roma Illustrate, 92), Rome, 1966, 72 f.Google Scholar; Table II, V.

²¹ My observations agree with those in Table II, V (a) for the church. Salterini noted a change in modulus in the bell-tower, which, she concluded, may indicate a separate building phase. I agree with that conclusion.

²² Forcella, , Iscrizioni, V, 117 f.Google Scholar, nos. 341 and 342.

²³ Gandolfo, F., ‘Riempiego di sculture antiche nei troni papali del XII secolo’, Atti della Pontificia Accademia Romana di Archeologia (Serie III) vol. XLVII, 1976, 203 ffGoogle Scholar. esp. 211 ff.

²⁴ The Liber Pontificalis reports with regard to the Robert Guiscard disaster, ‘Immo ipse cum suis totam regionem illam in qua aecclesiae sancti Silvestri et sancti Laurentii in Lucina site sunt penitus destruxit et fere ad nichilem redegit …’, LP, II, 290Google Scholar.

²⁵ Forcella, , Iscrizioni, V, p. 119Google Scholar, no. 344.

²⁶ My observations mostly agree with those in Strutture Murarie II, Table II, X. Besides, M. E. Avagnina noted sloping mortarbeds in the clerestory and suggested that the bricks there were made specifically for this building. Her 5 × 5 modulus in the campanile is lower than mine.

²⁷ We take our date from Kinney, D., S. Maria in Trastevere from its founding to 1215, unpublished Ph. D. thesis, New York University, 1975, 190 ff.Google Scholar, who clarifies the documentary evidence related to the date of construction and shows that the consecration of the church often attributed to Pope Alexander III (1159–81) was in fact done by Pope Alexander II (1061–73), before the rebuilding by Innocent II (1130–43), cf. Strutture Murarie II, 206.

²⁸ My information agrees with that in Table II, XIV, except that I did not observe any stilatura.

²⁹ Inscription on architrave; cf. Krautheimer, , Corpus, I, 1937, 272Google Scholar, who gives a more precise date of 1157.

³⁰ My observations agree with those in Table II, VIII (b). Garibaldi gives dimensions for brickwork in other parts of the church and conventual buildings, which did not seem to me to be firmly dated. Nor was it clear how much information she took from Prandi, A., Il Complesso monumentale … di SS. Giovanni e Paolo, Rome, 1953Google Scholar and how much resulted from her own observations.

³¹ Krautheimer, , Corpus, II, 1959, 13Google Scholar, quoting LP, II, 451Google Scholar: (Pope Clement III) ‘… claustrum apud sanctum Laurentium extra muros ordinavit …’.

³² Table II, IX, I, 1 and 2. In general our dimensions are similar. Garibaldi observed finta cortina over the brickwork in the cloister, while I found it only in the nave and narthex of the church, see also notes 12 and 36.

³³ Inscription given by Forcella, , Iscrizioni, XI, p. 161, no. 297Google Scholar; see also Krautheimer, , Corpus, I, 1937, 305 f.Google Scholar, who identifies large parts of the church as a much earlier early Christian structure.

³⁴ I find the entry for this church in Strutture Murarie II, Table II, VII, confusing. Type 1 (b) relies on ‘visual analysis’ and no dimensions are given; the description of type 1 (c) is not clear. I was not convinced that Garibaldi had distinguished properly between the early Christian and later medieval parts of the building. At S. Clemente C.S. found falsa cortina pointing in the vertical mortar joints of opus listatum, Table II, III (2), but I have not noticed it there.

³⁵ Krautheimer, , Corpus, II, 1959, 14Google Scholar, gives documentary evidence.

³⁶ My dimensions agree with those in Table II, IX, II.2 (where only one reading of the modulus is given) and 3 (where the modulus is slightly higher than mine).

I believe the masonry described in Table II, IX, II.1 dates from the nineteenth century, see below and note 86.

When discussing the walls of the thirteenth-century nave and narthex, Garibaldi seems not to have noticed that they are built of brickwork (with finta cortina) on the inside and of opus saracinescum on the outside. In this regard my observations tally with those in Krautheimer, , Corpus, II, 1959, 36, 41, 43Google Scholar, rather than with hers.

³⁷ Inscription given in Forcella, , Iscrizioni, VIII, p. 290, no. 718Google Scholar; see also Krautheimer, , Corpus, IV, 1970, 4Google Scholar.

³⁸ This corresponds with the figures given in Table II, XVII, Phase II, first modulus, taken in the blocking of the phase I colonnade. Since the Chapel of S. Silvestro was indeed built into the earlier phase I colonnade, but outside the phase II church, it seems to me Salterini has given precisely this 1246 modulus; see note 17 above.

³⁹ Malmstrom, R., S. Maria in Aracoeli at Rome, unpublished Ph. D. thesis, New York University, 1973, 51 ffGoogle Scholar.

⁴⁰ Malmstrom, R., ‘The twelfth century church of S. Maria in Capitolio …‘, Roemisches Jahrbuch für Kunstgeschichte … 16 (1976) 1 ffGoogle Scholar.

⁴¹ Forcella, , Iscrizioni, p. 119Google Scholar, no. 261 for the original dedication; p. 120, no. 263 for repairs in 1277. One of the bells, with the date on it, was in the church when I undertook this study.

⁴² It looks more like a family tower than a Romanesque campanile.

⁴³ Krautheimer, , Corpus, V, 1977, 12Google Scholar.

⁴⁴ Ibid., 21 and fig. 37.

⁴⁵ Ibid., 23; as Krautheimer's assistant, I measured this modulus in 1974.

⁴⁶ For the date, 1295, see Krautheimer, , Corpus, III, 1967, 8Google Scholar and Gardner, J., ‘Pope Nicholas IV and the decoration of S. Maria Maggiore’, Zeitschrift für Kunstgeschichte 36 (1973) 1 ffCrossRefGoogle Scholar.

⁴⁷ Although I have seen this masonry, I have not been able to measure it.

⁴⁸ M. E. Avagnina found a lower modulus than I did in the S. Lorenzo in Lucina campanile, see Table II, X (b) and note 26 above.

⁴⁹ Krautheimer, , Corpus, II, 1959, 184Google Scholar. Avagnina, Table II, X (a), also found this masonry unusual.

⁵⁰ See previous note.

⁵¹ Table II, VII, 1 (c); XII; XVI, 1; XXIII, 1 (a).

⁵² At S. Giovanni a Porta Latina (Table I, H) I found a lower modulus, between 29 and 31 cm. in parts of the building which seem definitely to date from the later Middle Ages.

At S. Maria in Cosmedin (Table I, B) I did sometimes find a high measure, but more frequency one of c. 30–31 cm.; see note 19 above.

At S. Prisca, although I found a high modulus averaging 34 cm. in the low wall which originally supported the right colonnade (perhaps a remnant of an earlier edifice?) and which is now on the right of the small square in front of the church, I measured a 5 × 5 modulus of 32 cm. in the medieval apse wall and one of 28, 29·5 and 30·5 cm. in the right aisle wall. The left aisle wall of this church is built of opus listatum, with tufelli, mixed with blocks of travertine, 18·5, 20 or 24·5 cm. long and 12, 15·5 or 19 cm. high; these courses of stone alternate with 3, 4 or 5 rows of bricks. (This masonry was not mentioned by Salterini, see Table II, XVI).

At S. Vitale, in the piers marked with stilatura, accessible in the courtyard to the right of the church, I measured a 5 × 5 modulus, which sometimes rose as high as 33 or 33·5 cm., but which was most often 31 or 31·5 cm.

⁵³ At S. Prisca Krautheimer describes the outer wall of the sacristy (= the wall to the right of the square in front of the church) as ‘laid to a modulus from four to five courses per Roman foot’ (= c. 35–29·56 cm. for a 5 × 5 modulus); the brickwork of the apse with a modulus of ‘five brick courses per Roman foot’ (= 29·56 cm.); and that of the south aisle wall ‘five and a half to six courses per Roman foot’ ( = 25–27 cm.), Krautheimer, , Corpus, III, 1967, 269 and 272Google Scholar.

At S. Vitale he says the piers with falsa cortina pointing are faced with large bricks with a modulus of five courses per Roman foot ( = c. 29·56 cm.). He also describes brickwork with a much lower modulus (6 courses to the Roman foot, or a 5 × 5 modulus of 24·63 cm.) and opus saracinescum in most of the clerestory, which he would date c. 1368 from documentary evidence. Krautheimer, , Corpus, IV, 1970, 322 fGoogle Scholar.

⁵⁴ Table II, V and XIX (d); at S. Lorenzo in Lucina, Avagnina (Table II, X (b)) found brickwork with the same modulus in the campanile, but my dimensions do not correspond with hers, see note 48 above.

At S. Giovanni a Porta Latina (Table II, VII, 2) Garibaldi recorded a very low modulus, 23–24 cm., in the walls of the campanile, which she also considered a later addition. I have found that modulus in buildings of the second half of the thirteenth century and I would agree with her conclusion.

At SS. Giovanni e Paolo (Table II, VIII (d)) Garibaldi mentions brickwork with a 26–28 cm. modulus blocking some openings in the upper floors of the campanile, but this is surely late and of uncertain date.

⁵⁵ Table II, XVIII, Phase II; III, 1(a). The documentary evidence for dating the successive late medieval phases of SS. Quattro Coronati is given in notes 15 and 37.

At S. Clemente an inscription on the bishop's throne in the apse states that Cardinal Anastasius began and completed the work of rebuilding the church. For his date of office, c. 1099–1125, see Boyle, L., , O.P., ‘The date of consecration … of S. Clemente’ in: San Clemente Miscellany II: Art and Archaeology, ed. Dempsey, L., , O. P., Rome, 1978, 1 ffGoogle Scholar. Another inscription suggests that a certain Petrus completed the campaign begun by Cardinal Anastasius, see Gatti, G., ‘Di un nuovo monumento epigrafico relativo alla basilica di S. Clemente’, Bullettino della Commissione archeologica communale XVII (1889) 467 ffGoogle Scholar.

⁵⁶ Notes 17 and 38 above and Table I, A, Phase II.

⁵⁷ Lloyd, J. E. Barclay, The architecture of the medieval church and conventual buildings of S. Clemente in Rome, c. 1080–c. 1300, unpublished Ph. D. thesis, London University, 1980, esp. 82 f.Google Scholar; 133; and for the south wall of the atrium, 130. In the near future a revised version of my thesis will be published by the Dominicans at S. Clemente as vol. III in their San Clemente Miscellany series.

Salterini would like to date the medieval church of S. Clemente to the third decade of the twelfth century, or perhaps a little later, because she believes the brickwork and the oculi in the clerestory resemble those at S. Croce in Gerusalemme, Strutture Murarie II, 189Google Scholar (Table II, VI), but I am not convinced by her arguments. The type of masonry I found at S. Clemente was common in Rome all through the twelfth century; oculi appear as early as 1116 in the aisle walls of the smaller rebuilding of SS. Quattro Coronati—now blocked, they are visible in the present convent refectory. I do not believe one can normally use masonry analysis and window typology alone to date a building to a particular decade in the later Middle Ages in Rome.

⁵⁸ In their entry on the nave and narthex of S. Lorenzo f.l.m. (1216–27) Table II, IX, they did not measure the brickwork modulus, but they gave one reading by Krautheimer of 28 cm., which they mistakenly quoted as a 3 × 3, rather than a 5 × 5 modulus.

⁵⁹ For S. Saba, Table II, XVIII.

At S. Sisto Vecchio medieval brickwork is accessible in the blocking of the Early Christian colonnade left of the present High Altar. It consists of brick fragments, 8, 9, 26 or 33 cm. long and 3–5 cm. high, with mortarbeds 2–3·5 cm. high. The mortar is crumbly and full of chalk; it is sometimes smoothed over the bricks, but there is no falsa cortina pointing. A 5 × 5 modulus is usually 28, 29 or 29·5 cm., although occasionally a height of 26·5 or 32 cm. was measured.

For the restructuring of the early Christian basilica of Sisto, S., Geertman, H., ‘Ricerche sopra la prima fase di S. Sisto Vecchio in Roma’, Rendiconti—Atti della Pontificia Accademia Romana di Archeologia 41 (1968/1969) 219 ffGoogle Scholar. and Krautheimer, , Corpus, IV, 1970, 163 ff.Google Scholar, with further references documenting the later medieval campaign.

⁶⁰ Krautheimer, , Corpus, III, 1967, 109 fGoogle Scholar. describes the brickwork at S. Martino ai Monti as having 0·50 m. for 10 courses of bricks and mortar, i.e. a 5 × 5 modulus of 25 cm., near the ground, but a higher modulus, 0·29 m. or 0·31 m., for 5 rows of bricks and mortar higher up; ibid., III, 1967, 248 f. describes brickwork at S. Prassede as having 6 courses to the Roman foot, i.e. a 5 × 5 modulus of 24·63 cm. In Strutture Murarie I, passim, it can be seen that a 5 × 5 modulus of c. 28 cm. is often found in Carolingian brickwork. This brickwork differs from twelfth century opus testaceum in its wavy rows of bricks.

⁶¹ The first rebuilding of SS. Quattro Coronati is usually dated shortly after the incursion of Robert Guiscard in 1084, see note 15; the piers with eleventh-century frescoes in the lower church of S. Clemente are usually given a similar date, see Toubert, H., ‘Rome et le Mont-Cassin …’, Dumbarton Oaks Papers 30 (1976) 3 ffGoogle Scholar.

⁶² Above, and note 59.

⁶³ For a description of this lime finish, sometimes referred to as falsa cortina, see note 10 above.

⁶⁴ I have found this treatment used frequently in undated walls, for example in the conventual buildings at S. Clemente. The technique, as we noted above, note 10, is sometimes referred to as falsa cortina.

⁶⁵ Avagnina et al., Strutture Murarie II, passim, frequently try to distinguish between stilatura in the centre or the lower part of the mortarbeds. I have not found such differences consistently used by medieval Roman masons.

⁶⁶ In this I do not agree with the conclusion of Salterini, C. in Strutture Murarie II, 245 f.Google Scholar, that stilatura was used only in the first half of the twelfth century. V. Garibaldi in the same study, on the other hand, mentions stilatura in the cloister of S. Lorenzo f.l.m. (1187–91), Table II, IX, 1 and 2.

⁶⁷ Table I, A, phase II; my Ph. D. thesis, cited in note 57, 82 f.; Table I, C; E; and H; above, note 59.

⁶⁸ Giovenale, op. cit., 93 f., 243 f.; Malmstrom, R., ‘The twelfth-century church of S. Maria in Capitolio …’, Roemisches Jahrbuch für Kunstgeschichte … 16 (1976) 10Google Scholar and note 19; Salterini, C. in Strutture Murarie II, 246Google Scholar, says ‘falsa cortina’ was used as a decorative finish.

⁶⁹ Cf. C. Venanzi, op. cit., 36 f., who makes a similar point. All the bell-towers are undated, except that of S. Silvestro in Capite, said to have been built by Innocent III (1198–1216), Krautheimer, , Corpus, IV, 1970, 151Google Scholar.

⁷⁰ For these dates, note 61 above.

⁷¹ Krautheimer, , Corpus, III, 1967, 277 ff.Google Scholar, esp. 291 f., 296 f. (for masonry) and 280 f. (for dates). He describes stilatura repointing on the Roman wall as making it appear as if ‘at first glance the entire wall … (was) … rebuilt in the Romanesque period’ (p. 296). Although the practice of marking mortarbeds in this way goes back to Roman times, this was evidently a medieval repointing.

⁷² McClendon, C., The medieval abbey church at Farfa, unpublished Ph. D. thesis, New York University, 1978, 67 and 89Google Scholar, figs. 70a, b, for falsa cortina pointing; p. 32 and 105 f. for the date of the eleventh century consecration.

⁷³ Table I, K; Table II, II.3 (1).

⁷⁴ Table I, K.

⁷⁵ Krautheimer, , Corpus, I, 1937, 247Google Scholar for the date.

⁷⁶ J. E. Barclay Lloyd, op. cit., 83, in Wing C of the canonry.

⁷⁷ Krautheimer, , Corpus, IV, 1970, 322Google Scholar: ‘The piers are built of small broken bricks indiscriminately mixed with lumps of tufa; where a modulus can be measured we find as many as seven courses per Roman foot’ (= a 5 × 5 modulus of c. 21·1 cm.); the arcade and spandrels rebuilt at that time had a modulus of six courses to the Roman foot (= a 5 × 5 modulus of c. 24·63 cm.); see also note 53 above.

⁷⁸ See above and notes 12, 32, 36, for finta cortina in S. Lorenzo f.l.m.; Table II, XIX for that in the campanile at S. Salvatore in Curtibus.

⁷⁹ Table I, L.

⁸⁰ See my Ph. D. thesis, cited in note 57, p. 84.

⁸¹ In the East basilica at S. Lorenzo f.l.m. (579–90), for example, the tufelli average 6–7·5 cm. in height and 15–18·5 cm. in length and they alternate regularly with one row of bricks, cf. Krautheimer, , Corpus, II, 1959, 66Google Scholar. The authors of Strutture Murarie I, passim, give similar dimensions: the height of tufelli usually 6–8 cm., occasionally 10 cm., the length up to c. 32 cm., but usually shorter; an exception is in the apse foundation wall of S. Nicola de Calcarario, p. 133 ff., which, however, they date c. 1130. T. L. Heres, op. cit., 30, gives an average size of 15 × 7 × 7 cm. for tufelli in the third century and says they became smaller in the fourth and fifth centuries; at S. Sebastiano, p. 343, she gives a height ranging from 6·5–8·5, but averaging 7·3 cm.; at S. Vitale, p. 367, a height ranging from 6·4–9·5, but averaging 7·5 cm.

⁸² For the date of rebuilding, see note 55 above.

⁸³ See note 52 above.

⁸⁴ An inscription on the lintel of the main door gives the date 1113; the church was consecrated in 1174 or 79 by Pope Alexander III (1159–81), Kehr, R. F., Italia Pontificia, I, Rome and Berlin, 1906, 112Google Scholar.

⁸⁵ I do not agree with all the conclusions about opus mixtum (opus listatum) expressed by Garibaldi, V., Strutture Murarie II, 244 fGoogle Scholar. I do not think the use of tufa was more sporadic at the beginning, more frequent at the end of the twelfth century; nor do I think it was intentionally used mainly to repair brickwork walls. Its use is evident all over the city, not just in buildings outside the Walls. Often, as we shall see, it was used in foundations and in domestic or monastic architecture.

⁸⁶ Table II, IX, II, 1, and Strutture Murarie II, fig. 48. In this masonry three rows of tufa blocks alternate with three courses of bricks. That V. Vespignani reinforced the walls along the north aisle of S. Lorenzo f.l.m. is well documented in the Istituto di Storia d'Arte e di Archeologia, Raccolta Lanciani, Cartella XLV, quoted by Krautheimer, R., Josi, E. and Frankl, W., ‘S. Lorenzo fuori le Mura in Rome: excavations and observations’, Proceedings of the American Philosophical Society 96 (1952) 3, 6Google Scholar and note 30.

⁸⁷ Table II, XXII; it was given to the Cistercians in 1140 by Innocent II, who is said to have rebuilt the monastery and church, which was consecrated in 1221 by Honorius III.

Since the publication of Strutture Murarie II A. M. Romanini has asserted that the opus listatum in the church and monastery dates from two building phases in the eleventh and twelve centuries, idem, ‘La storia architettonica dell'abbazia delle Tre Fontane a Roma. La fondazione cistercense’, in: Mélanges Anselme Dimier, III, vol. 6, 1983, 653 ff.Google Scholar, esp. 679 ff.

In January, 1982 Jeremy Blake, R.I.B.A. and I made an architectural survey of this medieval abbey, which we intend to publish in the near future.

⁸⁸ Krautheimer, , Corpus, III, 1967, 270Google Scholar.

⁸⁹ Krautheimer, , Corpus, IV, 1970, 222Google Scholar and figs. 176, 178 and 179.

⁹⁰ de Campos, R., I Palazzi Vaticani, Bologna, 1967, 22 f.Google Scholar, who mentions opus saracinescum, with tufa blocks measuring c. 13 cm. in height and c. 15 cm. in length.

Steinke, K. B., in her book, Die mittelalterlichen Vaticanpaläste und ihre Kapellen … (Studi e Documenti per la storia del Palazzo Apostolico Vaticano V) Vatican City, 1984Google Scholar, gives surprisingly little information about the techniques used in the palace. She does, however (pp. 29 f. and 40) mention a type of opus saracinescum in a three-apsed building on the site of the present Campo Santo Teutonico, which she would like to date to the ninth century, despite mural decoration of the twelfth and thirteenth centuries. While I believe it is possible that there was a Carolingian variant of opus saracinescum, this example sounds to me like an undated later medieval rebuilding of the ninth century triclinium.

On a visit to the Vatican Palace with L. Frommel, R. Krautheimer, F. Mancinelli and B. Schapiro in 1984 I was able to make some cursory observations and measurements of its medieval masonry. In the ‘cucina diplomatica’ at the base of a pier there was a stretch of neat brickwork, with a 5 × 5 modulus of 30 or 31 cm. and no falsa cortina pointing. Elsewhere in that room the exposed brickwork had a low modulus of 23, 24 or 25 cm. for five courses of brick and mortar. This second modulus was also found in the Sala degli Archivi. The medieval walls of the palace were frequently built of opus saracinescum: for example, in the ‘chapel’ beneath that of Nicholas V the tufelli were 11, 12, 14 or 16 cm. long and 4, 5·5 or 6 cm. high and a 5 · 5 modulus measured 32 or 32·5 cm. In a tower close to the present sala del sinodo the tufelli were 10, 15, 17, 27 cm. long and 7 or 8 cm. high; the corners of the tower had quoins 31 or 35 cm. long and 24, 26·5 or 37 cm. high. (In the opinion of Prof. L. Frommel this tower was built in the fifteenth century).

Clearly, a new architectural survey of the Vatican Palace and a thorough study of its masonry are needed, if the medieval building phases of this important monument are to be clarified.

⁹¹ See note 53 above.

⁹² Amadei, E., Le Torri di Roma, Rome, 1969, 99Google Scholar. One has quoins similar to those in the tower of the Vatican Palace, referred to in note 90 above.

It would be interesting to know whether the dimensions of the tufelli and their moduli changed significantly in the period c. 1200–c. 1450.

⁹³ Table II, IX and XXIII.

⁹⁴ Krautheimer, , Corpus, passim: Strutture Murarie I, 151Google Scholar and fig. 45.

⁹⁵ Krautheimer, , Corpus, III, 1967, 270Google Scholar.

⁹⁶ See above, p. 240.

⁹⁷ Krautheimer, , Corpus, V, 1977, 34 ff.Google Scholar, figs. 17–20, 27 b and 28.

⁹⁸ Strutture Murarie I, 133 ff. and fig. 27.

⁹⁹ Table I, N, O and P.

¹⁰⁰ Table I, L.

¹⁰¹ In this I agree with the authors of Strutture Murarie II, 242 ff.

¹⁰² Serafini, A., Torri campanarie di Roma e del Lazio nel medioevo, Rome, 1927, I, 98 f.Google Scholar, figs. 257, 258 and 259.

¹⁰³ The Table records each technique; the buildings in which it is found; the walls examined; the date—underlined if secure, approximate dates if known, or undated; and references made to it in the text—in Tables I and II, in the text of this paper, or in the notes.