Reasons for the outbreak of war
Fuse of the war was Flanders region (present-day Belgium and the Netherlands). Then Flanders was European industrial developed region. Particularly in wool textile technology was very advanced. So here was the richest part of Europe.
Louis VII
Background
The United Kingdom monarch of golden bird-flower dynasty theoretically was France subjects, should be for the French King effect render one's services. Not only so, regardless of as Royal history intermarriage of in-laws with France, also was as France most powerful of feudal lords, once France throne appeared the situation-old King had no son, or because various causes no legitimate of throne heir.When the nobles struggled for the throne, the monarch of golden bird-flower dynasty was no doubt that to have participation game of qualification! So after the French King died, Edward III formally proposed requirements inherited the throne of France.