The Medici Chapels are an extension of the Basilica of San Lorenzo, built to celebrate and welcome the remains of the Medici family. The funeral of Giovanni di Bicci dei Medici was celebrated in San Lorenzo and his son, Cosimo the Elder, effectively the first lord of Florence, was later buried in an underground crypt in the church, placed in a pillar exactly beneath the central altar of the Basilica. From that moment on, the members of the Medici family were buried in that place until the dynasty died out. Giuliano dei Medici, who became Pope Clement VII, built a mausoleum to ensure the dignified burial of the family members. The Medici Chapels were completed in 1524 based on Brunelleschi's design. They can be reached from the rear of the church and are divided into three separate parts: the crypt, the Cappella dei Principi (Chapel of the Princes) and the Sagrestia Nuova (New Sacristy).
The crypt is the first room you enter from the Basilica: on the floor, you can see the tombstones of several members of the Medici family and other close relatives. In this place, you will find the tomb of Giovanni dalle Bande Nere and his wife Maria Salviati, the parents of Cosimo I. Giovanni was the son of Giovanni il Popolano and Caterina Sforza; Maria Salviati was the daughter of Lucrezia dei Medici and granddaughter of Lorenzo the Magnificent. Their marriage was particularly important, because it was the link that reunited the main branch with the commoner or cadet branch, from which the Grand Ducal branch descended.
Two flights of steps lead to the Cappella dei Principi. The chapel is a large octagonal room surmounted by the dome of the Basilica of San Lorenzo, which is the most impressive in Florence after Brunelleschi's dome. The chapel was designed by Cosimo I and completed by his son Ferdinando I, who embellished the room in a sumptuous way thanks to the rich Florentine mosaic inlays, which were accomplished thanks to the creation of the Opificio delle Pietre dure (Workshop of semi-precious stones). The tombs of the grand dukes belong to Cosimo I, his son Francesco I and his brother Ferdinando I, his grandson Cosimo II and great grandson Cosimo III, up to Anna Maria Luisa, the Electress of the Palatinate who was the last descendant of the dynasty. The sarcophagi we see are empty. The remains of the Grand Dukes are kept in simple spaces hidden behind the walls, in the Buontalenti crypt. A long corridor leads from the Cappella dei Principi leads to the Sagrestia Nuova, which was commissioned to Michelangelo by Pope Leo X and by Clement VII. The two beautiful monumental tombs dedicated to Lorenzo dei Medici, duke of Urbino and father of Caterina dei Medici, and of Giuliano dei Medici, duke of Nemours and son of Lorenzo the Magnificent, were built there. They both died very young. Michelangelo sculpted "Le Allegorie del Tempo" (The Allegories of Time) for these tombs: Day and Night for Giuliano and Dusk and Daybreak for Lorenzo, the symbol of the transience of earthly life and the decline of the cycle of life towards death. Lorenzo the Magnificent and his brother Giuliano dei Medici are buried under the altar. Michelangelo did not finish the work on the tombs in the Sagrestia Nuova, taking on an assignment that took to Rome.
A curiosity: Ferdinand I had planned to put the original Holy Sepulchre of Jerusalem, which he had tried in vain to buy, in the centre of the lavish Cappella dei Principi.