As a Patarene supporter of Pope Gregory VII and his reforms,[3] Bonizo was driven into exile following Henry IV's invasion of Italy in the Investiture Controversy.
[4] Sometime between late 1085 and early 1086,[5] while staying at Matilda of Tuscany's residence and after the death of Gregory, Bonizo began writing Liber ad amicum.
"[12] Based on his reading of the Book of Genesis (specifically chapters 21 and 26), Bonizo argues that Christians must humbly endure persecution from non-Christians but engage in physical violence against heretics.
[17] Bonizo proceeds to list a few notable Christian acts of religious violence as recorded in the Historiae Ecclesiasticae Tripartitae Epitome.
[19] Bonizo recounts in great detail Gregory's continued opposition to clerical marriage and simony,[20] while arguing that Henry is solely to blame for the current papal-imperial conflict.