The four gospels all say Jesus rose from the dead. They give us almost excessive details. Setting aside the biblical reports of the resurrection for the sake of scrutiny, we still have to make sense of the other solid facts: a) Jesus's body disappeared and has never been recovered; b) The Roman guards would not have allowed his body to be stolen, and all the authorities wanted him dead and gone for good. c) The disciples had no faith that he would rise from the dead, and they had no reason to even try to steal a dead man's body in light of who they had expected him to be—an invincible Messianic deliverer, who had failed. Now, it is an historical fact that the disciples later believed that Jesus had risen. Is there a reasonable explanation for this? 

Yes, there is. Consider the evidence.