The Basilica of San Lorenzo Maggiore is a Church in Milan, named after the Christian Martyr Saint Lawrence. Located in the city Park "Basil", which is also home to the Basilica of Sant Eustorgio and Colonna Romana San Lorenzo.

There are different opinions about how and when was built the Basilica of San Lorenzo, including that which relates the Foundation of the Church by the 4th century. It is known that in the 16th century the Church was restored, but retaining its original Byzantine architecture with a dome and four towers resembling the spires of Istanbul's Aya Sofia. Recent stratigraphic study of the walls allowed us to identify five stages of the structure of the Basilica, starting from the time of Theodosius I (4th century) and ending with the early Lombard period (6-8th century).

The Basilica of San Lorenzo has the shape of a quatrefoil double-hull and consists of an open Central area surrounded by deambulatory semicircular bypass gallery. The shape of the quatrefoil of the Church give four Exedra – deep niches with five arches each. A characteristic feature of Byzantine architecture are the Emporia – balconies on which prayed exclusively women. Unfortunately, the Emporia survive, and multicolored decorations. The dome of the Basilica was rebuilt in Baroque style after the original collapsed.

Over the long history of the Church, it was built several chapels, the most notable of which is octagonal Cappella di Sant Aquilino, standing to the South of the building of the Basilica. Probably the chapel was conceived as a Roman mausoleum – it preserves valuable paleo-Christian mosaics of the 4th century. Also in the chapel are buried the remains of the Martyr Saint Aquilino, whose name it bears. Deserve the attention of the reliquary of the 17th century, made by Lombard architect Carlo Caravela, and the fresco by Carlo Urbino on the wall behind the main altar.

In the square before the Basilica you can see the so-called Column of San Lorenzo is one of the few buildings of the ancient Roman Mediolanum (predecessor of Milan), dated to 3rd century and probably built by order of Emperor Maximian. In the former apse of the Basilica is now a Park.