Rolous Group Temples

+ Bakong is the first temple mountain of sandstone constructed by rulers of the Khmer empire at Angkor near modern Siem Reap. In the final decades of the 9th century AD, it served as the official state temple of King Indravarman I in the ancient city of Hariharalaya, located in an area that today is called Roluos.

+ Lolei is the northernmost temple of the Roluos group of three late 9th century Hindu temples at Angkor, the others members of which are Preah Ko and the Bakong. Lolei was the last of the three temples to be built as part of the city of Hariharalaya that once flourished at Roluos, and in 893 the Khmer king Yasovarman I dedicated it to Shiva and to members of the royal family. The name “Lolei” is thought to be a modern corruption of the ancient name “Hariharalaya,” which means “the city of Harihara.” Once an island temple, Lolei was located on an island slightly north of centre in the now dry Indratataka baray, construction of which had nearly been completed under Yasovarman’s father and predecessor Indravarman I. Scholars believe that placing the temple on an island in the middle of a body of water served to identify it symbolically with Mount Meru, home of the gods, which in Hindu mythology is surrounded by the world oceans.

+ Preah Ko (The Sacred Bull) was the first temple to be built in the ancient and now defunct city of Hariharalaya (in the area that today is called Roluos), some 15 kilometers south-east of the main group of temples at Angkor. The temple was built under the Khmer King Indravarman I in 879 to honor members of the king’s family, whom it places in relation with the Hindu deity Shiva.

Look this up on Wikipedia