Complex sentence: Siger de Brabant (Sigerus, Sighier, Sigieri Sygerius), ("c." 1240--1280s), 13th century philosopher from the southern Low Countries was one of the major proponents and inventors of averroism.
Split into simpler sentences: Siger de Brabant (also Sigerus, Sighier, Sigieri or Sygerius), ("c." 1240--1280s), was a 13th century philosopher from the southern Low Countries. He was one of the major proponents and inventors of averroism.