Complex sentence: As the An Shi Rebellion shook up the Tang Court and caused its emperor to flee, Tibet overtook the entire territory of Tuyuhun until internal turmoil developed within the Tibetan Government and massive revolts brought an end to its ruling.
Split into simpler sentences: As the An Shi Rebellion shook up the Tang Court and caused its emperor to flee, Tibet overtook the entire territory of the Tuyuhun. Internal turmoil developed within the Tibetan government and massive revolts brought an end to its ruling.