CHAPTER SIX

A SCIENCE OF TIME: AND HIS SUCCESSORS

1. Bacon, the Calendar, and the Passion of Christ

The acute criticism of the ecclesiastical calendar voiced in theCompotus emendatus of Reinher of Paderborn and—in somewhat more subdued form—in the works of Constabularius and Roger of Hereford fell on fertile ground in the following century, during which three well-known English scholars went on to pen influential treatises on the reform of the calendar, which took account of the deficiencies both of the Julian calendar with respect to the sun and the 19-year lunisolar cycle with respect to the moon. The three men in question were the astronomer John of Sacrobosco (ca. 1195–ca. 1256), who wrote a treatise De anni ratione (ca. 1232/35),1 Robert Grosseteste (ca. 1170–1253), chancellor of Oxford University and bishop of Hereford, who wrote a Compo- tus correctorius (ca. 1220/30), and—most importantly—the Franciscan polymath Roger Bacon (ca. 1214/20–ca. 1292).2 Bacon’s views on the calendar have gained particular fame for the strident tone in which they were expressed and for the fact that he was the first to present this kind of criticism to the only person in Latin Christendom who could have possibly authorized the desired change: Clement IV (1265–68), to whom he addressed both his Opus

1 Theeditio princeps of this text can be found in John of Sacrobosco, Libellus de Sphaera, ed. Philipp Melanchthon (Wittenberg, 1538), Br–H3r. On the background, see Olaf Pedersen, “In Quest of Sacrobosco,” Journal for the History of Astronomy 16 (1985): 175–221; Jennifer Moreton, “John of Sacrobosco and the Calendar,” Viator 25 (1994): 229–44. 2 TheCompotus correctorius of Robert Grosseteste was edited by Steele as an appen- dix to Bacon, Compotus, 232–40. On the background, see Duhem, Le système, 3:411–13; Richard C. Dales, “The Computistical Works Ascribed to Robert Grosseteste,”Isis 80 (1989): 74–79; Jennifer Moreton, “Robert Grosseteste and the Calendar,” in Robert Grosseteste, ed. James McEvoy (Turnhout: Brepols, 1995), 77–88; Moreton, “On Not Editing Grosseteste”; Matthew F. Dowd, “Astronomy and Computus at Oxford Uni- versity in the Early Thirteenth Century: The Works of Robert Grosseteste” (PhD Diss., University of Notre Dame, 2003), 200–304. 156 chapter six maius and the supplementing Opus tertium (1266/68).3 In his writ- ings, Bacon referred to the present state of the calendar as “unbear- able,” “horrible,” and “ridiculous.” Not unlike Reinher of Padborn, he connected these charges with the complaint that Muslims, Jews, and other unbelievers were laughing at the Church’s expense about its inability to calculate the date of Easter with sound astronomical means. Addressing the Pope directly, he proclaimed that despite the fact that the Council of Nicaea had once prohibited any changes to its Easter computus, it was now time for the Holy See to finally step up and “relieve the church from this monstrum.”4

3 See Roger Bacon, Opus majus, ed. John Henry Bridges, 3 vols. (Oxford: Clarendon Press, 1897–1900), 1:269–85. This section is largely identical with Roger Bacon,Opus tertium (chap. 67–71), edited in his Opera quaedam hactenus inedita, vol. 1, ed. J. S. Brewer (London: Longman, Green, Longman, and Roberts, 1859), 272–95. Accord- ing to Bacon (ibid., 273–74), the chapters found in the Opus tertium were supposed to be a revised and corrected version of what had been included in the Opus majus. Since both versions are nowadays found to be identical, it seems that the original was replaced at a later point. See Opus majus, 1:269n2. There are numerous difficulties concerning the relationship between the Opus majus, minus and tertium. In particu- lar, it is doubtful whether the latter was ever finished and sent. These questions have little or no bearing on the matters discussed here. For further detail, see Stewart C. Easton, Roger Bacon and His Search for a Universal Science (Oxford: Blackwell, 1952), 144–66, and Eugenio Massa, Ruggero Bacone (Rome: Edizioni di Storia e Letteratura, 1955), 7–80. On Roger Bacon’s life and works, see Lynn Thorndike,A History of and Experimental Science, 6 vols. (New York: Columbia University Press, 1923–58), 2:610–30; Theodore Crowley,Roger Bacon (Louvain: Éditions de l’Institut supérieur de philosophie, 1950); David C. Lindberg, Roger Bacon’s of Nature (Oxford: Clarendon Press, 1983), xv–xxvi; Jeremiah Hackett, ed., Roger Bacon and the Sciences (Leiden: Brill, 1997); Hackett, “The Published Works of Roger Bacon ,”Vivarium 35 (1997): 315–20; Robert Bartlett, The Natural and the Supernatural in the Middle Ages (Cambridge: Cambridge University Press, 2008), chap. 4. 4 Bacon , Opus tertium, 272–73: “Secundum quod expono circa ecclesiastica est de corruptione kalendarii, quae est intolerabilis omni sapienti, et horribilis omni astronomo, et derisibilis ab omni computista. Unde omnes instructi in astronomia, et in computo, et in talibus, mirantur quod tam abominanda falstias sustinetur; sed impossibilie est quod sustineretur, nisi quia illi, qui habent auctoritatem super hac correctione, non sunt exercitati in astronomia, et computo, et in hujusmodi. Nullam enim percipiens talem abominationem susteneret eam. Et ideo quilibet sapiens Chris- tianus, qui haec tractat, ostendit articulos istius corruptionis et docet remedia. Non tamen aliquis praesumit tradere kalendarium correctum propter hoc, quod concilium generale prohibet ni quis mutet kalendarium sine licentia sedis apostolicae speciali. Et hoc justum est. Sed illa sedes beatissima deberet hoc monstrum tollere de eccle- sia.” Ibid., 293: “Atque philosophi infideles, Arabes, Hebraei, et Graeci . . . abhorrent stultitiam quam conspiciunt in ordinatione temporum quibus utuntur Christiani in suis solemnitatibus.” Bacon wrote this plea for calendar reform in 1267, as can be gathered from ibid., 277.