Simplify the following text for a Grade 11 native English-speaking person.
Original: Don Philip Rupasinghe Gunawardena ( 11 January 1901 â `` 26 March 1972 ) introduced Trotskyism to Sri Lanka , where he is a national hero , known as ` the Father of Socialism ' and as ` the Lion of Boralugoda ' .
Simplified: Don Philip Rupasinghe Gunawardena ( 11 January 1901 â `` 26 March 1972 ) introduced Trotskyism to Sri Lanka .