I found a different date for the annunciation to Mary in Ottoman calendars and in medieval historical sources, viz. the first of December! Biruni, a medieval historiographer from Khorezm in Central Asia, reports that the Nestorian church dates this event on December 1. Also Ottoman calendars of the 18th and 19th centuries mention both dates (25 March and 1 December) for this event. Has anyone got an explanation for the date of 1 December, that is explained by Biruni with a miraculous pregnancy of the Virgin of only 25 days.