As the bells rang out across the courtyard of the Church of the Holy Sepulchre, the priests began to sing a deep, low prayer. Heads bowed over candles, and escorted by people bearing aloft large gold crosses, they made their way to a platform at the heart of the ancient square. The ceremony on Holy Thursday, in which the Greek Orthodox Patriarch of Jerusalem washes the feet of 12 monastic priests to commemorate the Last Supper, is one of many Easter rituals that have taken place in the Old City of Jerusalem for hundreds of years. For Christians, there is...