Of the original structure, the great apse with its tall columnar arcades and the fine campanile remain.

The nave and transepts of the cathedral were rebuilt in the Gothic style in the 14th century, while the west front was begun in 1204 by Guido Bigarelli of Como, and consists of a vast portico of three magnificent arches, and above them three ranges of open galleries adorned with sculptures.

This cedar-wood crucifix and image of Christ, according to the legend, was carved by his contemporary Nicodemus, and miraculously conveyed to Lucca in 782.

The tomb of Ilaria del Carretto by Jacopo della Quercia of Siena, the earliest of his extant works was commissioned by her husband, the lord of Lucca, Paolo Guinigi, in 1406.

The rustic incised Latin inscription refers to ancient pagan mythology: "This is the labyrinth built by Dedalus of Crete; all who entered therein were lost, save Theseus, thanks to Ariadne's thread" (HIC QUEM CRETICUS EDIT.