Author: Atarah al'Norahn
Masenashar was one of the nations of the Free Era. It was located near the central part of the Westlands. To the north was Oburun, with Roemalle to the east, Dal Calain to the southeast, Farashelle to the south, Oman Dahar to the west, and Ito the northwest. Eventually, this area of land became what is now unclaimed land in around the Black Hills.
Around FY 943, fighting over Guaire Amalasan had begun in Masenashar.
By FY 963, Masenashar had fallen to Artur Hawkwing.
It is mentioned in "The World of Robert Jordan's 'The Wheel of Time'" that sometime around 450 AB there was a Queen of Masenashar named Sulmara. Apparently, she was a renegade Aes Sedai. It is said that the details differ in various versions of this story, but in the end, all of the stories agree that upon capture, Sulmara spend the rest of her life working in the stables of Tar Valon. However, the date for this occurrence, 450 AB, must be wrong because this would place it during the time of the Compact of Ten Nations, before the Trolloc Wars. It is possible that this actually happened around 450 FY and that it was a typo.
Reference: The World of Robert Jordan's "The Wheel of Time"