(Italian: Arco di Costantino) is a triumphal arch in Rome dedicated to the emperor Constantine the Great. The arch was commissioned by the Roman Senate to commemorate Constantine's victory over Maxentius at the Battle of Milvian Bridge in AD 312. Situated between the Colosseum and the Palatine Hill, the arch spans the Via Triumphalis, the route taken by victorious military leaders when they entered the city in a triumphal procession. Dedicated in 315, it is the largest Roman triumphal arch, with overall dimensions of 21 m (69 ft) high, 25.9 m (85 ft) wide and 7.4 m (24 ft) deep. It has three bays, the central one being 11.5 m (38 ft) high and 6.5 m (21 ft) wide and the laterals 7.4 m (24 ft) by 3.4 m (11 ft) each. The arch is constructed of brick-faced concrete covered in marble.

The Dacians were the ancient Indo-European inhabitants of the cultural region of Dacia, located in the area near the Carpathian Mountains and west of the Black Sea. They are often considered a subgroup of the Thracians. This area includes mainly the present-day countries of Romania and Moldova, as well as parts of Ukraine, Eastern Serbia, Northern Bulgaria, Slovakia, Hungary and Southern Poland. The Dacians and the related Getae spoke the Dacian language, which has a debated relationship with the neighbouring Thracian language and may be a subgroup of it. Dacians were somewhat culturally influenced by the neighbouring Scythians and by the Celtic invaders of the 4th century BC.