This chapel is a complete contrast in style. The project was begun by Cardinal Guido Ascanio Sforza di Santa Fiora when he was archpriest of the basilica in 1556, but there was a hiatus before construction could start. Unfortunately, Guido died in 1564 and the project was taken up by his brother Cardinal Alessandro Sforza. Recently discovered documents proved not only that the design of the chapel was Michelangelo's own but the great artist had personally supervised "every detail, day by day" until his death. The chapel is dedicated to the Virgin Mary of the Assumption, and was begun in 1562. After Michelangelo's death Tiberio Calcagni and Giacomo Della Porta, two of his pupils, had put the finishing touches to it. But by then Michelangelo had already put the imprint of his genius on it.