You might be interested in this thread by u/JimeDorje and this by u/Qweniden

What I got.

Following the Rebellion of the Northern Magadha Rebels in northern parts of modern day Bangladesh, Sikkim and Bhutan, under the reign of Emperor Tridu Songtsen, all the monasteries of Tibet under the authority of Lhasa were given the time limit of two months to declare the Bengali rebels as apuñña or sinned and thus that the Bengali Buddhists had མནའ་བཟས་པ or betrayed the teachings of the Buddha. This was accepted by most Tibetan Monasteries which declared 'Sacred Conflict' between all Tibetan Buddhists and Sinned/Betrayed Buddhists who were portrayed as the enemy rebels. [1]

Furthermore, it is well known that Emperor Tride Tsuktsän of Tibet declared 'Holy Conflict' between Tibet and the Transoxiana Muslims in support of its Turgesh Allies, which had a royal writ declared and signed by all the prominent Lamas of Tibet giving their assent to the use 'religious force' against the Muslim encroachment in Central Asia which was till then under influence of China and Tibet [2]

[1][2] - Buddhism and Empire The Political and Religious Culture of Early Tibet