Complex sentence: Crowley and Hirsig proceeded to Tunis, Tunisia, where, dogged by continuing poor health, he unsuccessfully tried to kick his heroin addiction, and began writing what he termed his "autohagiography", "The Confessions of Aleister Crowley".
Split into simpler sentences: Crowley and Hirsig proceeded to Tunis, Tunisia, where his poor health continued and he unsuccessfully tried to kick his heroin addiction. He began writing what he termed his "autohagiography", "The Confessions of Aleister Crowley".