Jayavarman II settled north of the Tonle Sap and founded Hariharalaya, at modern day Roluos.
His follower on the throne ( a cousin of his ) went back to Roluos ( Hariharalaya ).
Among the " Roluos Group " of temples there are some of the earliest permanent structures built by Khmer.
The early Khmer temples built in the Angkor region and the Bakong temple in Hariharalaya ( Roluos ) employed stepped pyramid structures to represent the sacred temple-mountain.
That could explain why he preferred to has his residence at Koh Ker and not at Roluos ( Hariharalaya ) or at Yashodharapura ( Angkor ) like the kings before him.
Glazed wares first appear in the archaeological record at the end of the 9th century at the Roluos temple group in the Angkor region, where green-glazed pot shards have been found.
At his capital city Hariharlaya, Roluos at present, Indravarman I built Pr?% K?( Preah Ko ), which he dedicated to his maternal father and grandfather, and the dynasty founder Jayavarman II . His palace was located at Prei Monti.