Wikipedia
Theiddat (, ; 1375–1407) was the heir-presumptive of Ava from 1400 to 1406 during the reign of King Minkhaung I of Ava. Theiddat was the key figure in securing his elder brother Minkhaung I's claim on the throne of Ava. In the early days of Minkhaung's reign, Theiddat personally led an army to put down a major rebellion. When Minkhaung named his eldest son Minyekyawswa heir apparent in 1407, Theiddat felt betrayed, and fled south and joined the service of King Razadarit of Hanthawaddy Pegu, which was amidst fighting the Forty Years' War (1385–1424) with Ava.
It turned out that Theiddat could not betray his brother. In 1407, Theiddat, who was with a special group of Hanthawaddy forces who were waiting to ambush Minkhaung, gave a warning to his brother at a critical moment, allowing him to escape. Theiddat was duly executed by Razadarit for his warning.