After the murder of Me Agtsom by his two ministers, Lang Nyesig and Bel Dongtsab in 755, Takdra Lukhong and Shang Gyalsig quickly put down the rebellion and had rebels purged.
The young prince Trisong Detsen succeeded, Takdra Lukhong was appointed nang lön chen po ("Chief Inner Minister"), and became the second highest officials just below the regent Mashang Drompakye, both were followers of Bon and opponents of Buddhism.
Trisong Detsen decided to promote Buddhism when he was 20 years old but was strongly opposed by Takdra Lukhong, Mashang Drompakye, and even the queen Magyal Dongkar.
Mashang predicted that if the emperor promoted Buddhism, all scriptures of Bon would be abandoned, the end of the world might be nigh and the empire would collapse.
Trisong Detsen hosted a famous debate between Buddhist and Bon supporters, and the winner would be recognised as the "state religion" in Tibet.
He regained the emperor's trust and later appointed gung lön chen po ("Chief Minister"), the highest official position in Tibet.