Sire de la Ferte 

Quarterly, or and sable; on the first quarter an eagle, gules, armed azure. On the second a lion rampant a la queue fourche argent. A member of La Ferte in England married an heiress of the Briewers.

Guillaume de La Ferte Maint Englies unt acrabente - Roman de Rou.

Roman de Rou: a translation by Ian Short

The lords of Vitry, Ivry, Montbray and Sai were there also, and the lord of Ferté laid low many an Englishman. These men inflicted grave damage on the enemy, though not without incurring serious losses themselves.