Simplify the following text for a Grade 13 native English-speaking person.
Original: Herman ( `` Norrie '' ) Northrop Frye , CC , FRSC ( July 14 , 1912 â `` January 23 , 1991 ) was a Canadian literary critic and literary theorist , considered one of the most influential of the 20th century .
Simplified: Herman Northrop Frye , CC , FRSC , usually called Northrop or Norrie , ( July 14 , 1912 â `` January 23 , 1991 ) was a Canadian literary critic and literary theorist .