The present appearance of the Cathedral of Ravenna is relatively recent. It was designed by Giovanni Francesco Buonamici and completely re-built between 1734 and 1735 on the site where Bishop Urso had erected the former cathedral of the city (Basilica Ursiana) at the end of the 4th century. The original floor is now over 3 metres below ground level. Partly concealed by a great arched portico, the façade leads to the interior of the church divided into a central nave and two side aisles. The almost 50m-high dome, wholly frescoed by Giovan Battista and Andrea Barbiani, rests on a tambour topped by a lantern and illuminated by eight big windows. The round bell tower, located next to the cathedral, goes back to the 10th century.Remains of the original construction are preserved in the Archiepiscopal Museum, that hosts early-Christian works such as the marble ambo dating back to the episcopacy of Agnello (557 - 570) and decorated with 36 panels showing animal figures.