In the spring or summer of 1294, a Franciscan friar named Robert of Leicester put the finishing touches to a lengthy treatise on time reckoning, which had been requested by Richard Swinfield, the bishop of Hereford ( 1282-1317).1 According to Robert's own introduction, his work was written "in a rough style" and intended to deal with the "calculation of time, so that knowledge of the flow of the ages may be obtained more readily and, as I suppose, more certainly, provided that God deems it worthy to guide my intention".2 At first glance, these words might give the impression that the present text is yet another medieval work on the computus (or compotus, as it used to be spelt in the thirteenth century), of whose kind one can still find thousands of preserved copies in European libraries. The principal subject of this rich and variegated genre was the date of Easter, which had to be cal culated anew for each year on the basis of a lunisolar cycle - a calendrical device that integrated the disparate lengths of the lunar month and the solar year. On top of this dry and technical base, the average computus tract piled juicy layers of further information, mainly culled from astronomy and arith metic, but also encompassing subjects such as theology, philosophy, etymol ogy and medicine. In the case of the most influential of all computus treatises, written in the eighth century at the monastery of Jarrow (Northumberland)
1 This article presents some of the results of a two-year research project on "Medieval Christian and Jewish Calendar Texts", directed by Sacha Stern (University College London) and funded by the Leverhulme Trust. A full study and critical edition of Robert of Leicester's treatise, the principal topic of this article, will appear as part of my monograph Medieval Latin Christian Texts on the Jewish Calendar: A Study with Five Editions (Leiden: Brill, forthcoming 2014). The treatise is preserved in Oxford, Bodleian Library (hereafter, Bod.), MS. Digby 212 (s. XIV"2), fols. 2r~7v, 8v-iov; Erfurt, Universitáts- und Forschungsbibliothek, Bibliotheca Amploniana, qu. 361 (s. XIV [med.]), fols. 8orb-85rb.
2 Bod., MS. Digby 212, fol. 2r: "In nomine domini nostri Ihesu Christi qui est auctor temporum et ipsorum etiam plenitudo presens opusculum de temporum compoto ad decursorum seculorum notitiam promptius et, ut estimo, si tamen intentionem meam Deus dignetur dirigere, certius opti nenda stilo rudi conscripsi ac in 4 partículas . .. divisi."
by the Venerable Bede, the main text came in conjunction with a world chronicle, which gave readers a precise account of the numbers of years that had flown between important world historical events, from the creation of the world to the present.3 Even the title of Robert of Leicester's work, as given at the end of one of the two preserved manuscript copies,4 is reminiscent of Bede's work: De ratione temporum (Robert) vs. De temporum ratione (Bede), both of which may be translated as "on the method of time reckoning". What else, then, but Bede's model could Robert have had