The Arch of Constantine was built to honour Emperor Constantine and his victory at the Battle of the Milvian Bridge, on the river Tiber. It was a crucial battle between two Roman Emperors, Constantine, and Maxentius. The former’s triumph paved his way to becoming the sole ruler of the Roman Empire, annulling the previous form of government, the Tetrarchy. The Arch was completed in 315 and was built right along the route of the historic military triumphs.