^{page 1 note 1} Baedae Opera Historica, ed. Plummer, C., 2 vols. (Oxford, 1896)Google Scholar; Bede's Ecclesiastical History, ed and trans. Colgrave, B. and Mynors, R. A. B. (Oxford, 1969).Google Scholar

^{page 1 note 2} HE 1.22 and v.22.

^{page 1 note 3} I am very grateful to Dr A. Fletcher for much advice and information about astronomical details.

^{page 1 note 4} HE iii.17.

^{page 1 note 5} HE v.21.

^{page 1 note 6} O'Connell, D. J., ‘Easter Cycles in the Early Irish Church’, Jnl of the R. Soc. of Ants. of Ireland 66 (1936), 67–106.Google Scholar

^{page 2 note 1} Dionysii liber de Pascbate, Migne, Patrologia Latina 67, cols. 483–508; ed. Krusch, B., Studien zur christlich-mittelalterlichen Chronologie, Abhandlungen der Preussischen Akademie der Wissenschaften, Phil.-Hist. Klasse 7, no. 8 (Berlin, 1938).Google Scholar

^{page 2 note 2} Newton, R. R., Medieval Chronicles and the Rotation of the Earth (Baltimore and London, 1972), pp. 22–7.Google Scholar

^{page 2 note 3} The figures were provided by Dr A. Fletcher from Goldstine, H., ‘New and Full Moons 1001 BC to AD 1651’, Memoirs of the Amer. Philosophical Soc. 94 (1973)Google Scholar. Dr Fletcher observes that the figures are not known to the nearest minute, but for present purposes a few minutes either way are immaterial.

^{page 3 note 1} Bickerman, E. J., Chronology of the Ancient World (London, 1968), p. 18.Google Scholar

^{page 3 note 2} HE v.21.

^{page 4 note 1} Grosjean, P., ‘La Date du colloque de Whitby’, AB 78 (1960), 240Google Scholar n. 1.

^{page 4 note 2} Bedae Opera De Temporibus, ed. Jones, C. W. (Cambridge, Mass., 1943), p. 29Google Scholar. This edition contains De Temporum Ratione and the letter to Wicred.

^{page 5 note 1} HE v.21.

^{page 5 note 2} Epistola ad Wicredam, Venerabilis Bedae Opera, ed. Giles, J. A. I (London, 1843), 157 and 162Google Scholar; Opera De Temporibus, ed. Jones, pp. 321 and 325.

^{page 5 note 3} Green, A. R., ‘Anglo–Saxon Sundials’, AntJ 8 (1928), 489–516CrossRefGoogle Scholar; Taylor, H. M. and Taylor, J., Anglo–Saxon Architecture (Cambridge, 1965), p. 236Google Scholar. In his introduction to Bede's Opera De Temporibus (pp. 126–7), Jones discusses ‘horologica consideratione’ (p. 237 of text) in terms of a sundial, but would appear to underrate the difficulty of determining the equinox by this means. I am indebted to Dr P. Hunter Blair for a reference demonstrating Bede's knowledge of contemporary dials: In Regum Librum XXX Quaestiones, Corpus Christianorum Series Latina 119, ed. Hurst, D. (Turnholti, 1962), 316Google Scholar (c. xxv).

^{page 5 note 4} HE 1.1.

^{page 6 note 1} ‘For if the earth were not at the centre, it can be recognized that days and nights could not be equal; which ‘sights’ confirm very strongly, since at the time of the equinox sunrise and sunset are seen on the same line, whereas sunrise at midsummer and sunset at midwinter fall on their own line.’ Plinii Naturalis Historia, ed. and trans. Rackham, H. ii (London, 1949)Google Scholar, c. 69. There are further remarks on sundials, gnomons and shadows in cc. 74–8. Rackham's translation of ‘binoculars’ for dioptrae is unhappy.

^{page 6 note 2} See the article ‘dioptra’ in Pauly-Wissowa, , Real-Encyclopadie v (Stuttgart, 1905)Google Scholar, cols. 1073–9. The term is applied to instruments used in surveying and by astronomers for measuring the angular separation of various celestial and terrestrial objects.

^{page 7 note 1} HE 111.4.

^{page 7 note 2} HE v.21.

^{page 7 note 3} Simplified from O'Connell, ‘Easter Cycles’, p. 106.

^{page 8 note 1} Beaujeu, J., ‘Science in the Greco–Roman World’, Ancient and Medieval Science, ed. Taton, R. (London, 1963), p. 330.Google Scholar

^{page 8 note 2} Councils and Ecclesiastical Documents relating to Great Britain and Ireland, ed. Haddan, A. W. and Stubbs, W. in (Oxford, 1873), 271.Google Scholar

^{page 8 note 3} Saints' Lives and Chronicles, ed. Jones, C. W. (Ithaca, N.Y., 1947), p. 6.Google Scholar