In 250, after over 200 years of evangelistic effort, Christians still made up only 1.9 percent of the empire. By the middle of the next century, though, about 56 percent of the population claimed to be Christians. More resources: • Evangelism in the Early Church, by Michael Green, dwells on both the New Testament and later periods. As the adviser on evangelism to the archbishop of Canterbury, his zeal for spreading the gospel shines through his well-researched history. • Encyclopedia of Early Christianity,