Complex sentence: Another influence for King's non-violent method was Thoreau's essay "On Civil Disobedience", which King read in his student days influenced by the idea of refusing to cooperate with an evil system.
Split into simpler sentences: Another influence for King's non-violent method was Thoreau's essay "On Civil Disobedience", which King read in his student days. He was influenced by the idea of refusing to cooperate with an evil system.