Epiphanius, bishop of Salamis on Cyprus from about 367 to 402, was a witness to and participant in the troubled era after the Council of Nicaea. His "Panarion" or medicine chest is an historical encyclopaedia of ideas and movements he considered heretical, and of the replies Christians ought to make to them. Book II and III deal with the Trinity, the Person of Christ, the divinity and personality of the Holy Spirit, Manichaeism, penance, matrimony and celibacy, monastic regulations, and the Christian Calendar, all hotly contested topics in the 4th century.