At the present time, the only known manuscript of Berceo's Martirio de San Lorenzo is the eighteenth-century copy that belonged to Padre Ibarreta, and Solalinde expresses the conviction that the Sánchez edition of the poem is based on the Ibarreta manuscript. On several occasions Sanchez mentions the fact that he had at hand the Ibarreta manuscript, and he likewise states that he had his own copy of several of Berceo's poems and that he used the Ibarreta version “para cotejar algunas que yo tenía, y copiar las que me faltaban.” That there is a close relationship between the Sánchez and Ibarreta versions of the Martirio de San Lorenzo is evident from the following facts; in both versions the poem is incomplete, containing only 105 stanzas; both versions have five verses in stanza 15; both versions use, consistently, the forms, ome, omes, sancto, sanctidat, lazdrar, judgar, nunqua; and they conform in the use of the exceptional forms cipdad 10d, cipdat 12d, Katolicos 2d, Karidad 10b, Karidat 47b. Furthermore, the three specific errors of construction or legibility mentioned by Sánchez are also found in the Ibarreta manuscript: the omission of Dios in 10b, omission of the rhyme word in 102d, and omission of seven letters in avrie despecho 105d.