News reports note that Pope Benedict XVI will enter the Dome of the Rock when he visits Jerusalem in May. If so, this will be an instance in which Benedict ventures a little further than Pope John Paul II did in relations with Muslims - John Paul stood outside the shrine when he visited Jerusalem in 2000, but did not enter it.The background story of this breathtaking, 1,300-year-old shrine was very much in the foreground that day, as I recall. A group of Palestinian demonstrators had gotten quite close to the pope and his entourage, shouting insults at the Palestinian officials who hosted John Paul. "Shame on you!" one of the demonstrators yelled. "Saladin took the keys; now you have handed them over to the pope."The Dome of the Rock has long figured in the contentious relations between Muslims and Christians. It was built large enough to outshine the Church of the Holy Sepulcher, and it contains large inscriptions that denounce the central beliefs of Christianity. Saladin won it back from the Crusaders in 1187.So it will be an interesting moment when a pope who was once the subject of angry demonstrations in many Muslim countries enters the Dome of the Rock - an important gesture on the part of the pope and his host, the grand mufti of Jersualem.