The Treaty of Montreuil arranged the betrothal of Prince Edward of Caernarfon and Isabella of France, shaping Anglo-French relations for decades.
Key Facts
- Drafted
- 19 June 1299
- Ratified by Edward I
- 4 July 1299
- Ratified by Philip IV
- 3 August 1299
- Penalty if Philip defaulted
- £100,000 fine
- Penalty if Edward defaulted
- Forfeiture of Gascony
- Eventual marriage date
- 25 January 1308, Boulogne-sur-Mer
By the Numbers
Location
Cause → Event → Consequence
The 1294–1303 Gascon War between England and France created urgent diplomatic pressure on both Edward I and Philip IV to negotiate terms that might resolve territorial disputes over Gascony and stabilize relations between the two crowns.
Negotiated at Montreuil on 19 June 1299 by English envoys including Henry de Lacy and Amadeus V of Savoy, the treaty arranged the betrothal of Edward's son Prince Edward of Caernarfon to Philip's daughter Isabella, with severe financial and territorial penalties for either party's default.
The treaty was supplemented by the Treaty of Chartres and ultimately superseded by the 1303 Treaty of Paris, which finalized the betrothal. Prince Edward, by then Edward II, married Isabella at Boulogne-sur-Mer on 25 January 1308, a union later described by contemporaries as bringing great unhappiness to both parties.
Political Outcome
Betrothal of Prince Edward of Caernarfon and Isabella of France agreed; Gascony secured conditionally; war negotiations continued toward the 1303 Treaty of Paris.
Anglo-French relations strained by active Gascon War since 1294
Diplomatic framework established via royal betrothal, moving toward eventual peace in 1303