Roots sink deeper. Dies Natalis Solis Invicti, translated as, “Birth of the Invincible Sun,” celebrated the birth of the Sun in Imperium Romanum prior to the coming of Catholicism, and with its coming, the celebration neatly switched to “Birth of the Invincible Son.” The word itself, natalis, meaning “of the birth,” changed over time as Latin split into different languages.
Latin is Nativitatis, Spanish is Natividad, and English is Nativity. Christus natus est is the Christmas refrain. Christmas is an English contraction of “Christ and Mass.”