The Tho Yor Arrival at Tython marked the zero year for the Standard Time dating system using TYA notation. 0 TYA took place in the year 36,453 BBY, 32,800 years before the Treaty of Coruscant, 35,453 years before the Ruusan Reformation and 36,418 years before the Great ReSynchronization. Following the initial settlement in 36,453 BBY, a secondary migration occurred over a millennium later.