“IHS” is commonly seen on gravestones. It’s a Christogram(abbreviation for the name of Jesus) reading IHS (“Iesus hominumsalvator”, or in English “Jesus, men’s saviour”).

Constantine’s ‘private/personal’ Christianity as opposed to his public (and wholly political) paganism is now well established by scholarship of his personal correspondence. As emperor, he was necessarily Pontifex Maximus of an officially and legally pagan state: had he neglected the duties of the office, the first ill omen or natural catastrophe would have served as “proof” of the anger of the gods at his neglect of them, and been sufficient provocation to depose or assassinate him. Constantine did not “convert on his death bed”: he was baptized on his deathbed which was a common practice in that time as in the 4th century many people feared there was no absolution for post-baptismal sin. It is evident from the sources that he had been inclined towards Christianity from and early age — his mother was a Christian, after all –that he had been considering converting for some time, and that the crucial change of mind came at the time of his famed vision of Christus Victor.