Christmastide is stretched between two feasts that celebrate the same mystery from different directions. In the West the anchor is Christmas, the Nativity kept on 25 December, first securely recorded at Rome in the Chronography of 354; in the East the older anchor is Epiphany on 6 January, the feast of manifestation, which in the Eastern churches celebrates above all the baptism of Christ in the Jordan. Each feast eventually crossed into the other's territory, Christmas travelling east in the late fourth century, Epiphany west, and the season between them became the bridge holding the pair together. The division of labour that resulted still shapes the calendars. In the West, Epiphany attached itself to the visit of the Magi, the manifestation to the nations, and the baptism was given its own feast at the season's end; in the East, 6 January remains the great feast of the waters, with the solemn blessing of rivers and fonts, and the Nativity stands beside it as a distinct celebration.
Churches keeping the Julian reckoning add a further layer, their 25 December falling on the civil 7 January, which is why the world's Christmases are spread across a fortnight. The season is therefore not one feast with an echo but a conversation between two ancient feasts, and its length is the space the conversation needs.