A compilation comprising as its chief elements the calendars of Rome, Carthage, and Syria. The nucleus of the work is the Roman calendar, with which were incorporated in part or in whole the calendars of other Italian cities and the calendar of Carthage. To the Western calendar thus formed, a later editor added the first part of the Syrian festival list. It is noteworthy that he has taken over with the Syrian calendar its Arian coloring, the commemoration of the two bishops Eusebius being retained and even that of Arius himself, his name appearing in the corrupted forms “Arthoci,” “Artotes,” or “Ari Thoti” in different MSS. The preface takes the form of a letter addressed by Chromatius of Aquileia and Heliodorus of Altinum to Jerome, asking him to send them the festal calendar of Eusebius, and a reply from Jerome in which he says he is sending a shortened form of the calendar with the names of the most notable martyrs arranged according to the months and days of the year. It is from this apocryphal correspondence that the martyrology takes its name. The preface is first cited by Cassiodorus in 544. Its final compilation probably dates therefore from between the late fifth and early sixth centuries, and was probably made in N Italy.