The tradition of prosopographies to which PBW belongs usually had simple definitions for the scope of their projects. “Byzantium” and “Byzantine sources” could be treated, without much distortion, as unproblematic ideas. The booklet accompanying the PBE I CD, for example, says:
The Prosopography of the Byzantine Empire aims to record all surviving information about every individual mentioned in Byzantine textual sources, together with as many as possible of the individuals recorded in seal sources, in the period 642-1261.
The eleventh and twelfth centuries, where PBW is now working, demand a more complex definition than the above. It has been qualified for present purposes in four ways:
- Over seals. The eleventh and twelfth centuries produced more Byzantine lead seals than earlier periods, and each seal, on average contains more information. Equally the rate of publication of such seals has increased in the years 2001-2011. The editors of PBW decided to give seals a higher profile than before. They were also forced, for practical reasons, to prioritise the new sources over older material like the publications of Schlumberger and Konstantopoulos. Many of the new seal publications represent the best-organised and most thorough prosopographical study of any Byzantine period yet attempted. The older material has thus been neglected in PBW and must now be added, together with the continuing flow of new seals, which threatens to become a flood with the beginning of on-line publication.
- Over geographical issues. From the second half of the eleventh century Byzantium came to rule only a small and fluctuating fraction of the territory the empire once dominated, demanding a decision of principle: was the prosopography to shrink with the empire, or to include an increasing non-Byzantine periphery? The decision was soon made: the Byzantium of PBW is the full empire left by Basil II, even if it was later steadily dismembered in east and west. In practice, however, work on the periphery has lagged behind that on central regions.
- Over languages and cultures. The current tranche of the prosopography has been prepared in the first decade of the twenty-first century. Events of this time have convinced the editors (like many others) that it is no longer legitimate to adopt a basically Eurocentric perspective on the Byzantine world, using (for example) Greek and Latin sources in the original, while turning to translations for other linguistic traditions. Arabic and the languages of Eastern Christendom will in principle be given equal status in PBW with Greek and Latin, especially in quotations provided in the original. But it is much easier to take such decisions of principle than to change editorial practice. The current version of the database has iconic areas of Arabic and Armenian script, but the achievement of equal status is still far off. Subsequent editions will move closer to the ideal picture set out in Byzantines and Crusaders in Non-Greek Sources, 1025-1204, edited by Mary Whitby, Oxford 2006, the publication of a British Academy Colloquium held under the auspices of PBW.
- Over the Crusades, which have a high profile in our time. Virtually all pilgrims and crusaders as they travelled belong to the Byzantium of PBW, as do those who settled in Antioch and Edessa, and even part of Tripoli. Of the later crusader states only Jerusalem had clearly been outside Basil II’s empire. But links were close: crusader citizens of PBW lands were often active in Jerusalem, while kings of Jerusalem were frequently involved in the north. The first four numbered crusades (and similar movements) were major events in Byzantine history, while connections with Byzantium itself form a significant dimension of the history of Jerusalem. Even many of the crusaders’ Muslim opponents and the various eastern Christians and Jews of the area might qualify for inclusion in the strict PBW definition for long or short periods, and their voices need to be heard. It seemed impractical to cover (say) three-quarters of the eastern history of the crusades whilst excluding the quarter which was outside the Byzantine World. A decision has therefore been made to add Jerusalem to the Byzantine world for the purposes of this prosopography.