In the marshy, coastal lowlands east of Venice lies Aquileia. Founded as a Roman colony in AD 181, Aquileia soon grew to be the fourth largest city in ancient Italy. When the city’s Basilica Patriarcale was built in 313, the floor was paved with a decorative carpet of mosaics. The church was remodeled in 1031, and so these intricate works of art became concealed for nearly a millennium. At the beginning of the 20th century, the ancient mosaic pavement was discovered below the nave floor and is thought to be the oldest surviving remnant of any Christian church. The designs incorporate both religious and pagan symbols, including animals, birds, trees, flowers, and geometric patterns.