Jean de Brienne, comte d'Eu

John I of Brienne (died 12 June 1294) was the son of Alphonso of Brienne and Marie de Lusigan.[1] His mother was the heiress of Eu, Seine-Maritime, and he succeeded his father as Count of Eu in 1270.

He married Beatrice, the daughter of Guy III, Count of Saint-Pol.[1] They had five children:

• John II of Brienne, Count of Eu
• Isabelle (d. 1302/07), married John II of Dampierre, Viscount of Troyes (d. c.1307)
• Jeanne (d. aft. 12 March 1325), married first Raymond VI, Viscount of Turenne (d. 1304), married second before 4 August 1314 Renauld, Lord of Picquigny, vidame of Amiens (d. 1315)
• Marguerite (d. 1310), married Guy, Viscount of Thouars (d. 1308)
• Mahaut (d. aft. 1328), married Alfonso de la Cerda

John died at Clermont-en-Beauvaisis in 1294.

Ref:
https://www.familysearch.org/tree/person/details/GJYD-1Q3

• M.A. Pollock, Scotland, England and France after the Loss of Normandy, 1204-1296, (The Boydell Press, 2015), 184.
• https://en.wikipedia.org/wiki/John_I_of_Brienne,_Count_of_Eu