Probably some parts of the Prasat Thom including the moat and the 1. (inner) enclosure were built before 921 AD. The sanctuary was expanded under the reign of Jayavarman IV and has now two surrounding walls inside of the moat. The first wall (inner wall) is made of brick; the second wall (outer wall) with a length of and a breath of is made of laterite. Two doors are in the east and in the west. The doors of the second wall have a cruciform plan. The doors of the first wall are smaller and not of cruciform layout. The plane between the first and second wall is completely overbuilt with rectangular structures, possibly later additions. In the center court is the sanctuary and opposite it are two socalled libraries. Behind the sanctuary on a rectangular platform stand nine towers in two rows (one of five, one four towers). Twelve smaller prasats in groups of three surround the platform. All 21 towers once housed lingas.