Although, there are several ahadith in Islamic resources about the time of his government which mentioned from 5 or 7 years to 309 years (the time of sleep of Kahf companion in that dark cave) - which is in fact, maybe it refers to the levels and ages of that government (its establishment five or seven years and the time of its completion 40 years and it final duration more than 300 years! Attention!) - but regardless of Islamic narratives, it is certain that these narrations and preliminaries are not for a short time government and certainly they are for a longtime government that is worth this much of efforts!