Ta Keo was the first ‘temple-mountain’ to be constructed entirely out of sandstone. Its construction began around 975; it served as Jayavarman V’s (968-c.1000) state temple. The building was not completed by the time of Jayavarman V’s death, but it was later resumed by his successor Jayaviravarman (1002-1010). One explanation for the unusual minimalism and simplicity of the stonework is that the monument was never completed.