Final answer:
William had support from various significant figures, such as feudal lords in the case of William the Conqueror and political figures during William of Orange's time, who later became William III of England.
Step-by-step explanation:
The significant figure that William had support from varied depending on the historical context being referred to. For instance, William of Normandy, also known as William the Conqueror, claimed that Harold Godwinson had pledged fealty to him, justifying his invasion of England. Additionally, William of Orange, who later became William III of England, had made it known he was willing to invade England to protect the nation and its religion. This act was aimed at countering the expansion of Louis XIV's France and gaining parliamentary support for his war efforts. The phrase "significant figure" in this context does not refer to a numerical value but rather an important person in history with political or royal influence.