From Tar Valon Library
Author: Atarah al'Norahn
Tsomo Nasalle was one of the great cities of the Age of Legends, before the Breaking of the World. It was one of the smallest of the great cities, twelfth in size and importance, with only Devaille and Tzora being smaller. No other information is available.
(Reference: The World of Robert Jordan's "The Wheel of Time")