"Why did Julius Caesar buy crayons" joke

"You know, except for the moustache, you look a lot like my mother."

"But I don't have a mustache."

"Yes, I know....but my mother does."

ALEXANDER The Great, Julius Caesar and Napoleon were watching a military parade in Moscow. Alexander could not take his eyes off the tanks.' If I had chariots like these,' he said,' I could have conquered the whole of Asia.'
Caesar eyed the missiles and said,' With such more...

When did Caesar reign? I didnt know he reigned. Of course he did, didnt they hail him?