 Some historians think that Jayavarman IV was an usurper; but, the majority of them believe that he was a legitimate ruler who could ascend to the throne because he married a half-sister of king Yasovarman I (889 – 900).What is certain is that the two sons of Yasovarman I (Harshavarman I, who ruled from 900 to 922 and Isanavarman II, who ruled from 922 to 925?