This may have helped him because he had the favor of both Christians and pagans. For example:
If he were to take the side of the Christians, then he'd have the pagans wanting to rebel against him. And vice-versa (which means "and the opposite" which would be if he took the side of the pagans, then he'd have the Christians wanting to rebel against him)
Therefore, since he chose to tolerate both of them, he'd have a more successful time.