Emile Mâle (1862-1954), The Gothic Image: Religious Art in France of the Thirteenth Century
, tr. Dora Nussey (1913; rpt. Oxford: Westview Press, 1973), p. 68:
In the Middle Ages the new year varied according to the locality. Gervase of Canterbury wrote in the beginning of the thirteenth century :— "Quidam enim annos incipiunt computare ab Annuntiatione, alii a Nativitate, quidam a Circumcisione, quidam vero a Passione." Thus the year began sometimes in March or April (the Annunciation or the Passion), sometimes on December 25 or January 1 (the Nativity or the Circumcision). In neighbouring towns such as Reims and Soissons the year began on the feast of the Annunciation (March 25) and on Christmas Day respectively.2 This explains why at St. Savin the zodiac begins with the Ram, that is with March.3 And Amiens probably chose December so that the year might open with Christmastide.4 An explanation may also be found for the unusual correspondence at Chartres of the month of January and the sign of Capricorn. In mediaeval days the signs of the zodiac did not correspond exactly with the length of each month, but were liable to encroach on the following one. We have evidence for this in a poem on the months by the monk Wandalbertus, who in the ninth century wrote of January—"Huic gemino praesunt Capricorni sidera monstro."5 "The sign of Capricorn presides over the two-headed monster (Janus)," that is over January.
2 See the Comte de Mas-Latrie, Trésor de chronologie, Paris, 1889, folio, col. 21-22. See also Giry, Manuel de diplomatique, Paris, 1894, 8vo, p. 114.
3 In Poitou in the Middle Ages the year began either on March 25, (the Annunciation) or on Easter Day which often falls in March. Giry, op. cit.
4 M. de Mas-Latrie, op. cit., states that at Amiens in the twelfth century the year began on Easter Eve, the day of the benediction of the paschal candle. One must therefore suppose either that it was no longer the custom in the thirteenth century, or that there is a mistake in the disposition of the signs.
5 Wandalbertus, monk of Prüm; Achery, Spicil., II, p. 57.