Otherstide

Otherstide was an annual Gallifreyan celebration honouring the figure known as the Other, who was part of the foundation of Time Lord society, along with Rassilon, Omega and three others. One Otherstide coincided with the Doctor's naming day and it was on another Otherstideeve that the First Doctor left Gallifrey, becoming a renegade. (PROSE: Lungbarrow)

Thirteen days after Otherstide, Thirteenth Night was celebrated by a cult. (PROSE: Managra)