Because the Hundred Years' War spanned such a long period in time, and because in reality it was actually a series of conflicts between England, France, and several other kingdoms and feudal territories, it is difficult to point to just two figures. However, two kings were, in fact, instrumental in the outbreak of the conflict. They were Philip VI of France and Edward III of England. Through marriage, English kings had a number of territories in what is now France, and Edward also had a claim to the French throne himself. This was one source of friction between the two kingdoms. Another was Philip's policy of supporting Scotland in that kingdom's ongoing conflicts with England. Edward also made military and hereditary alliances with rulers in Flanders, gaining influence over that rich commercial region as well as causing strategic headaches for Philip. Over time, the English began conducting raids in Northern France, and eventually Philip launched invasions of English territories on the continent. This began the series of campaigns known as the Hundred Years' War, which Edward launched on a full-scale (indeed really unprecedented in medieval history) basis based on his claim to the throne.