The Treaty of Montreuil provided for the betrothal of Edward of Caernarvon, later King Edward II of England, and Isabella of France, the daughter of Philip IV of France. It was drafted on 19 June, ratified by Edward I on 4 July, and amplified by the Treaty of Chartres on 3 August 1299. Under its terms, should Edward I default on the treaties, he would forfeit Gascony; if Philip defaulted, he would pay a fine of £100,000. It was said by contemporaries that the alliance brought "great unhappiness to both parties".