“Travelling to France under the guise of a diplomatic mission, Isabella began an affair with Roger Mortimer, and the two agreed to depose Edward and oust the Despenser family. The Queen returned to England with a small mercenary army in 1326, moving rapidly across England. The King's forces deserted him. Isabella deposed Edward, becoming regent on behalf of her son, Edward III. Many have believed that Isabella then arranged the murder of Edward II. Isabella and Mortimer’s regime began to crumble, partly because of her lavish spending, but also because the Queen successfully, but unpopularly, resolved long-running problems such as the wars with Scotland.

In 1330, Isabella’s son Edward III deposed Mortimer in turn, taking back his authority and executing Isabella’s lover. The Queen was not punished, however, and lived for many years in considerable style—although not at Edward III’s court—until her death in 1358.”

See Isabella of France - Wikipedia, the free encyclopedia.