A type of monumental arch that originated in Ancient Rome. There are two principal types; those with a single arch and those with a principal arch flanked by two smaller side arches. Both types had an attic storey above the arches. These arches were normally erected to commemorate a victorious military campaign, and often contained low relief sculpted panels illustrating important events. Among the most famous examples are the Arch of Constantine and the Arch of Titus, both in Rome.