<Li> From 25 March 754 AUC (today in AD 1). That second "Annunciation style" may have originated in Fleury Abbey in the early 11th century, but it was spread by the Cistercians . Florence adopted that style in opposition to that of Pisa, so it got the name of calculus florentinus . It soon spread in France and also in England where it became common in the late 12th century and lasted until 1752 . </Li> <Li> From Easter, starting in 754 AUC (AD 1). That mos gallicanus (French custom) bound to a moveable feast was introduced in France by king Philip Augustus (r . 1180--1223), maybe to establish a new style in the provinces reconquered from England . However, it never spread beyond the ruling élite . </Li> <P> With these various styles, the same day could, in some cases, be dated in 1099, 1100 or 1101 . </P> <P> The date of birth of Jesus of Nazareth is not stated in the gospels or in any secular text, but most scholars assume a date of birth between 6 BC and 4 BC . The historical evidence is too fragmentary to allow a definitive dating, but the date is estimated through two different approaches--one by analyzing references to known historical events mentioned in the Nativity accounts in the Gospels of Luke and Matthew, and the second by working backwards from the estimation of the start of the ministry of Jesus . </P>

When did they start using ad in dates