Bernini's next job was to make a special throne out of bronze, to hold an ancient wood and ivory throne that had been at the basilica for more than 500 years. It is called the "Cattedra Petri" or "throne of St. Peter". The bronze throne, with the old wooden throne inside it, is held up high at the end of the basilica, by four important saints who are called "Doctors of the Church" because they were all great writers and teachers. The statues are made of bronze. They are Saints Ambrose and Augustine for the Church of Rome and Saints Athanasius and John Chrysostum for the Orthodox Church. Above the chair is a window which is made not from glass but thin translucent stone called alabaster. The Dove of the Holy Spirit is in the middle of the window with rays of light spreading out into the basilica through a sculpture of golden clouds and angels. Bernini designed this to look like a window into Heaven. There was a great celebration when the chair was put in place on January 16, 1666.