William I

During William's childhood and up until his mid thirties, the ruler of Maine was a strong warrior by the name of Herbert Wake-dog. Herbert died in 1036. Later, when Herbert's succesor died, the citizens of Maine exiled his son and daughters. They then accepted Geoffrey Martel, the ally of the late King Henry, as their over-lord. Herbert II, the son of Herbert Wake-dog's succesor, and his still loyal barrons came to William with a plea to help him regain control of the land that is rightfully his by birth. If William agreed to help Herbert, Herbert agreed to let Maine be a fief of Normandy. He also had his sister marry William's oldest son. That way if Herbert should die without any children, the rule of Maine would go directly to William. So William agreed to these terms and fought alongside Herbert. In the end, Herbert and William were successful. Unfortunately, Herbert died within two years of his new rule. So that is how Maine came under William's rule.