The prayers for the dead, the Libri vitae and the cartularies which formed the subject of the preceding two chapters in this book provide an immediate conjunction between past and present time ; the dead are remembered in terms of the commemoration of their anniversaries in the present. Yet such texts also convey a very particular sense of the historical past in which chronology has a crucial role to play. The historical precedents for the records of the Libri vitae, furthermore, reinforce the sense of historical memory being formed in relation to particular books. Anton von Euw has uncovered precursors of the page layout with columns of the Liber viventium of Pfäfers in calendars and lists such as as the Calendar of 354 (BAV Barberini lat. 2154, fol. 7r) and its list of natales caesarum. The Cologne canon law collection (Cologne, Dombibliothek MS 212, fols 168v–169r) of the late sixth or early seventh century similarly places its list of pontifices romanorum in double arcades. The names of the popes from Peter to Gregory the Great are accompanied by a precise indication of their pontificate in years, months and days. A further influence, both conceptually and in the visual layout of the Libri vitae, may have been exerted by ivory diptychs such as the Diptychon barberini with its list of members of the Merovingian royal family (612–75) and Merovingian bishops from the fourth to the seventh centuries.