Both Dionysius and Bede regarded Anno Domini as beginning at the incarnation of Jesus, but "the distinction between Incarnation and Nativity was not drawn until the late 9th century, when in some places the Incarnation epoch was identified with Christ's conception, i.e., the Annunciation on March 25" (Annunciation style).
Tanto Dionisio como Beda consideraron Anno Domini a partir da encarnación de Jesús, pero a distinción entre a Encarnación e o Nadal non se elaborou ata finais do século IX, cando nalgúns lugares o momento da Encarnación foi identificado coa concepción de Cristo, é dicir, a Anunciación do 25 de marzo.