The Lower Church was built entirely in the Romanesque style, having low semi-circular ribbed cross-vaults over the nave and barrel vaults over the transept arms. However, the space has been greatly extended with a number of lateral and transept chapels added between 1350 and 1400. The main entrance to the nave is through an ornate Gothic doorway built between 1280 and 1300, and later enclosed with a simple Renaissance style porch of 1487 by Francesco di Bartolomeo da Pietrasanta (d. 1494). Set in the tympanum of the Gothic doorway is an ornate rose window which has been called "the eye of the most beautiful church in the world"