Sentence:  The earliest mention of the 25th of December as Christmas Day is found in an ancient catalogue of Church festivals about A.D. 354. And it is surprising to see with what alacrity the date was received and the <WSD>Nativity</WSD> celebrated throughout Christendom. 
Meaning of the word marked with <WSD> tags:  The festival celebrating the birth of Jesus, Christmas Day; the festival celebrating the birth of the Virgin Mary or the birth of Saint John the Baptist. (from 12th c.)