Tibetan history, or bad science-fiction novel?

[Byang-chub rgyal-mtshan] did everything in his power to improve the military strength and administration of his myriarchy, but lived in constant discord with the neighboring myriarchs of gYa-bzang and Tshal-pa. His enemy, the dPonchen of Sa-skya, took advantage of the situation to remove him, and after a resort to arms he was captured and convicted, but escaped.