Once a Roman soldier named Flavius Scollio, he and a small group were sent to investigate a falling star near their outpost in Africa. They discovered an alien craft instead and upon entering were attacked by an alien wearing a golden suit with an amulet attached. Flavius was able to catch the creature by surprise and took his helmet from him. When he put on the helmet, his mind was bombarded with incredible knowledge.
He raised what came to be known as the Black Tower of M'Kumbe in Wakanda. Inside he created a Roman Empire for himself and used captured Wakandans as slaves to his will, making them all silent. His abilities made them all live for centuries in silence and he renamed himself after the Roman Emperors he had served.
When the Fantastic Four investigated the tower, they allowed themselves to be captured. But when Frankie Raye attacked too soon, Gaius easily defeated her and removed the Fantastic Four's powers. He chose the Invisible Woman to be his Empress and even forced the Thing and the Human Torch to battle while under his telepathic influence in order to get her to agree.
Instead, she figured the source of his power was his helmet and removed it. When she did she revealed that no body was inside the armor. After all the time he spent inside, the strange amulet had slowly worn his body into nothingness, leaving only his mind. With the helmet removed, his mind was released and all his creations vanished.