Peter I, Duke of Brittany

Peter I
Peter represented on a window in Chartres Cathedral
Duke of Brittany
Reign1213–1221 (as duke)
1221–1237 (as regent)
PredecessorAlix
SuccessorJohn I
Co-rulerAlix
Bornc. 1187
Died26 May 1250 (aged 63)
Spouses
Issue
HouseDreux
FatherRobert II, Count of Dreux
MotherYolande de Coucy
Coat of Arms of Peter I, Duke of Brittany and his successors

Peter I (French: Pierre; c. 1187 – 26 May 1250), also known as Peter Mauclerc, was Duke of Brittany jure uxoris from 1213 to 1221, and regent of the duchy for his minor son John I from 1221 to 1237. As duke he was also 1st Earl of Richmond from 1218 to 1235.