Pope Julius I (337–352) is undoubtedly a key figure in the development of the papacy in the middle of the fourth century, and his significance has been increasingly realized in recent years. Not only was he a champion of the see of Peter and responsible for building a number of significant basilicas in Rome, including, as I have argued, Old St Peter's, but he also played a not insignificant part in the Arian controversy. Although he did not take the initiative, he was involved as a mediator between the Nicenes and their opponents, at the request of the latter, thereby beginning the tradition of appeals to Rome. So to have the first proper scholarly edition of his correspondence since the early eighteenth century is very timely. This learned book, volume 3 in the Library of Early Christianity series, contains the six surviving letters to and by Julius, with text, translation, introduction, and commentary. It is evidently the fruit of long, painstaking years of labor, building on recent scholarship and a detailed study of the manuscript tradition, so that what readers get is the most up-to-date and comprehensive study of Julius' correspondence. He is the first pope of whom we have a collection of letters, which by good fortune survive in the writings of others, the early papal archives, as Thompson notes, having probably been destroyed in the early fifth century. The collection includes two very significant pieces, Marcellus of Ancyra's famous letter to Julius (letter 1 in the collection), containing what Thompson and many scholars contend is the Old Roman Creed; and Julius' long letter to “the Eusebians” (letter 2), defending Athanasius and Marcellus against their charges. The others are a letter from Hosius of Cordova and Protogenes of Sardica defending the doctrinal statement of the (Western) Council of Sardica of 343 (letter 3), a letter from that synod (letter 4), a letter from Julius to the priests, deacons, and laity of Alexandria on the return of Athanasius in 346 (letter 5), and a letter from Valens of Mursa and Ursacius of Singidunum repudiating Arian ideas in 347 (letter 6). Interestingly, the pope was clearly bilingual, perhaps the last to be so, composing his two letters in acceptable Greek.

While it might seem that a disproportionately large portion of the book is dedicated to a detailed study of the manuscript tradition, that is undoubtedly necessary in order to establish the most accurate possible version of the text, without which no proper scholarly judgment can be exercised. Thompson is to be congratulated for his efforts in attempting to elucidate the text, with ample apparatus and judicious textual emendations based not on his own hunches but on the vast and invaluable resources of Thesaurus Linguae Graecae. Balancing that textual work is his very helpful general introduction to the life and works of Julius, covering not only the genuine letters, but also the fascinating topic of the false ones, including fourth-century Apollinarian and ninth-century Pseudo-Isidorean forgeries, as well as the printed editions. He ably situates Julius in his own context, skillfully guiding the reader through a very complex period, making good use of the latest scholarship while offering a perspective that differs from the usual approach centered on Athanasius. His introductions to the letters are equally helpful, and his English translation is clear and accurate. Particularly helpful is the chronological table of Julius' correspondence with the Eastern bishops (28). His bibliography of primary and secondary sources is very full, with the latter helpfully laid out (if with names in Latin). The book is nicely presented and has been very well proofread, exhibiting virtually no errors (although unfortunately the blurb on the dust jacket gets the gap between Julius' accession and Constantine's death—fifteen weeks—wrong). Thompson might perhaps have explored the relationship between Julius and the young emperor Constans as regards his Roman church buildings and his friendship with Athanasius.

This book, the first in a very promising projected series on the correspondence of the early popes, should certainly be in every research library. It would be valuable for advanced undergraduates and beyond who are studying late antiquity and fourth-century patristic history and theology, and should establish itself as the definitive scholarly critical edition.