Built between 1470 and 1476 by the will of Bartolomeo Colleoni, as mausoleum for his daughter Medea, the Chapel is dedicated to the Saints Bartholomew, Mark and John the Baptist. The actual building began, however, in the course of 1472 with the demolition of the sacristy of St. Mary The Greater. The architectural solution is in formal agreement with the Basilica, which is accompanied, in the octagonal drum and the cusp of the lantern. The choice of coverage in polychrome marble is in connection with the porch made by Giovanni da Campione, enhancing the features of the mausoleum and at the same time making the building suitable for liturgical celebrations. It's the masterpiece of Giovanni Antonio Amadeo, completed by successive additions that refer to Baroque Mannerism.