In the introduction to his History of the Crusades, Sir Steven Runciman noted the historian's professional preference for small fortresses of learning. Although comparatively easy to defend from the slings and arrows of critical assault, such castles of scholasticism (Runciman complained) command too narrow a field of fire to support exploratory excursions further afield. Deliberately – perhaps rashly – this book has attempted to avoid that particular charge. It covers a large slice of Jewish history during one of its most convulsive ages. Moreover, it has attempted to trace in manageable compass what are in retrospect two of the period's crucial themes: first, the incubation and institutionalisation of the ‘official’ rabbinic version of Israel's ordained constitutional chronology; second, and consequently, the propulsion of the rabbis and their disciples to positions from which they could claim (and sometimes attain) commanding communal authority.

Early rabbinic renditions and manipulations of the paradigm of the three ketarim mirror those developments. Approached as both a construct of power-sharing and as an implicit design for the examination of its operation, the model became a prominent article of constitutional polemic. Still more coherently, the intellectual architecture of the crown motif also articulated latent rabbinic notions about the very texture of ordained Jewish society.