Peter I, Duke of Brittany (b. c. 1187)
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.