Athinkhaya entered the royal service of King Narathihapate, and was later joined by his two brothers. The three brothers distinguished themselves in the war with the Mongols, which began in 1277. Athinkhaya married into the royal family, marrying Princess Saw U, a niece of the king and a granddaughter of King Uzana and Queen Thonlula. (His sister Hla Myat also married to Prince Thihathu, Viceroy of Prome.)