The online database published here is the product of Prosopography of the Byzantine World (PBW), a project covering the period AD 1025-1180, and represents a continuation of prosopographical work originally inspired by A.H.M. Jones in 1950, and sponsored since then by the British Academy. Jones’s aim was to bring to fruition a plan made earlier by Theodor Mommsen (1817-1903) within the Prussian Academy. With the help of files made available to Jones three volumes were published which between them covered the period AD 260-641: The Prosopography of the Later Roman Empire (PLRE) I-III, Cambridge, 1971, 1980, 1992. The sole editor of vols. II and III was J.R. Martindale, who had also worked with Jones and John Morris on vol. I. The overall plan of work was directed by a British Academy committee under the chairmanship of a succession of different scholars.