In 70 a.d., a few decades after the crucifixion of Jesus, the Roman army destroyed Jerusalem after a long siege. Perhaps no event has had more enduring reverberations. Judaism lost the Second Temple, the site of nearly all its rites, and the temple was never rebuilt. Jewish Christianity, centered in Jerusalem and led by James the brother of Jesus, soon disappeared beneath the waves of Gentile Christianity. Islam, too, was shaped by the defeat: today, on the former site of the Second Temple stands the Aqsa Mosque, the faith’s third most important devotional site. The Roman Church,…