In 1546, Michelangelo was appointed architect of St. Peters Basilica, Rome.[35] The process of replacing the Constantinian basilica of the 4th century had been underway for fifty years and in 1506 foundations had been laid to the plans of Bramante. Successive architects had worked on it, but little progress had been made. Michelangelo was persuaded to take over the project. He returned to the concepts of Bramante, and developed his ideas for a centrally planned church, strengthening the structure both physically and visually.[53] The dome, not completed until after his death, has been called by Banister Fletcher, the greatest creation of the Renaissance.[54]