Volume IV: The Tetrarchies and the Rise of the House of Constantine The fourth volume of the fully revised and expanded general catalogue of Roman coins extends coverage of the Imperial series from the accession of Diocletian in A.D. 284 down to the death of Constantine the Great more than half a century later. This was a period of great political, economic, and religious upheaval. It saw the establishment and collapse of DiocletianÕs tetrarchic system of government, a major financial crisis in the closing years of DiocletianÕs reign, and the adoption by Constantine of Christianity as the new state religion in the Roman Empire. The coinage itself underwent significant modifications at this time, notably the introduction of the gold solidus by Constantine in A.D. 310, the decline of the Diocletianic follis, and the checkered history of silver issues prior to ConstantineÕs reform in A.D. 325. The introductory articles are again included in this volume and, as with Volumes I-III, the Imperial biographies have been entirely rewritten and enlarged. There has been a major expansion of the catalogue listings and special emphasis has been placed on the precise form of the mint marks and the date of issue of each catalogue entry. This makes the book a much more valuable resource for students and collectors than was the case in earlier editions (or, indeed, any other general work on the subject). The final issues of the local coinage of Roman Egypt, struck at Alexandria, receive comprehensive coverage down to the termination of the series in A.D. 296-7. The number of illustrations incorporated in the text has been increased to over 800 out of a total listing of more than 4,400 types.