Before the revival of Greek learning in the fifteenth century, the Æsopic fables of classical antiquity were known in Europe through Latin collections derived from Phædrus. Two of these collections were particularly well known; one which goes under the name of Romulus, written in prose in the tenth century; and a metrical version of the larger part of Romulus, written in the twelfth century. This metrical collection, called in the Middle Ages Esopus, is now ascribed to Walter of England, but is often called Anonymus Neveleti. Another metrical version of Romulus was made a little later by Alexander Neckam, and the fables of Avianus, also, were known to some extent. These collections, with numerous recensions and derivatives in Latin, and translations into many different languages, form a body of written fable-literature whose development can for the most part be clearly traced. At the same time, beast-fables were extensively employed in school and pulpit, and were continually repeated for entertainment as well as for instruction. Thus there was current all over Europe a great mass of fable-literature in oral tradition. The oral versions came in part from the written fable-books; others originated as folk-tales in medieval Europe; others had descended orally from ancient Greece, or had been brought from the Orient. Many are still current among the people in all parts of Europe, and beyond. From this mass of traditional material, heterogeneous collections of popular stories, including beast-fables, were reduced to writing in Latin and in other languages. An example of this process is found in the Esope of Marie de France, the earliest known fable-book in a modern vernacular, which was translated into French in the twelfth century from an English work which is now lost. Forty of Marie's fables, less than two-fifths of the whole number, came from a recension of the original Romulus called Romulus Nilantii; the others from popular stories of various kinds. Similarly, the important Æsop of Heinrich Steinhöwel contains the Romulus fables in four books, followed by seventeen fables called Extravagantes, others from the recently published Latin version of the Greek fables, from Avianus, from the Disciplina Clericalis of Petrus Alphonsus, and from Poggio,—in all, nine books, printed in Latin with a German translation about 1480, and speedily translated into many languages (including English, by Caxton in 1484, from the French version). The Extravagantes, like other collections, and like the episodes of the beast-epic (little known in Italy), came from popular tradition. Many writers show by incidental references that they were familiar with fables, although they may not have regarded them as worthy of serious attention,—writers like Dante, and his commentator Benvenuto da Imola. Moreover, the animal-lore of the bestiaries and of works like the Fiore di Virtù is closely akin to that of the fables. It is evident, then, that the collections descended from Phædrus, important though they were, represented but a fraction of the fable-literature that was current in the Middle Ages.