Montfort Simon de

Mont·fort

 (mŏnt′fərt, môN-fôr′), Simon de Earl of Leicester. 1208?-1265.
French-born English nobleman who led the baronial opposition to Henry III. After his military victory over the king in 1264, Montfort was the effective ruler of England. In 1265 he called a representative legislature regarded as England's first full parliament.