By about the fourth century, pilgrimage to Jerusalem had become common enough that significant examples of a type of literature called the pilgrimage narrative have survived. Pilgrims talk of their burning desire to visit sites mentioned in the Old Testament as well as those associated with key events in the life of Christ. Emperor Constantine’s renovation of many of the holy places also made the practice more popular. After the Muslim conquest of Jerusalem and surrounding lands in 638, Christian access diminished somewhat, then improved for a while under the Crusaders’ Latin Kingdom. But during the Middle Ages, other sacred sites associated with famous saints gradually replaced Jerusalem as the goal of choice for countless European pilgrims. The shrine of Santiago de Compostela in northwestern Spain was a major site, said to be built around the remains of St. James the Apostle. Compostela came to symbolize Christian efforts against the infidel Muslims in the Holy Land. In more recent times the practice of pilgrimage to Jerusalem and associated holy places has revived with increased ease of travel. Some Christians also flock to lesser shrines associated with saints or apparitions of the Virgin Mary. Pilgrimage was once occasionally prescribed for individuals as penance for sins, but it has never been a central requirement for Christians as it has for Muslims.