The 12th century was a time of conflict and brutal power struggles. Under Suryavarman II (reigned 1113–1150) the kingdom united internally^[31] and the empire reached its greatest geographic extent as it directly or indirectly controlled Indochina, the Gulf of Thailand and large areas of northern maritime Southeast Asia. Suryavarman II commissioned the temple of Angkor Wat, built in a period of 37 years, which was dedicated to the god Vishnu. Its five towers representing Mount Meru is considered to be the most accomplished expression of classical Khmer architecture. In the east, Suryavarman II's campaigns against Champa and Dai Viet were unsuccessful,^[31]  though he sacked Vijaya in 1145 and deposed Jaya Indravarman III.^[32] The Khmers occupied Vijaya until 1149, when they were driven out by Jaya Harivarman I.^[33 ] However, territorial expansion ended when Suryavarman II was killed in battle attempting to invade Đại Việt. It was followed by a period of dynastic upheaval and a Cham invasion that culminated in the sack of Angkor in 1177.