Trisong Detsen
Trisong Detsen next sought to expand westward, reaching the Amu Darya and threatening the Abbasid Caliph, Harun ar-Rashid. The Caliph was concerned enough to establish an alliance with the Chinese emperor. King Trisong Detsen would be preoccupied with Arab wars in the west, taking pressure off his Chinese opponents to the east and north, until his rule ended in 797.