Before the arrival of Roman power, the territory of Marche was successively controlled by two distinct peoples. The Picenes, a population of Sabine origins, established themselves in the region during the ninth century BC and maintained dominion for several hundred years, developing a sophisticated culture evidenced by the elaborate burial goods found in their necropolises. In the fourth century BC, the Senones, a Celtic people stronger than the Picenes, swept into the region and displaced the existing inhabitants, though their control of Marche would prove relatively brief in the long sweep of history.
The fertile lands and strategic position of Marche soon attracted the attention of the expanding Roman Republic, which decisively defeated the Senones in 295 BC at the Battle of Sentinum. Following this victory, Rome established Sena Gallica as the first Roman colony in the region, systematically replacing existing settlements with Roman infrastructure and deporting both the Picenes and Senones to Campania. During the first century BC, the Augustan Reformation incorporated the territory into the fifth Roman region of Picenum, and the subsequent Imperial Age brought significant prosperity to the area, with the port of Ancona benefiting particularly from the Emperor Trajan’s military campaigns in Dacia at the beginning of the second century AD.
The Roman period left an indelible mark on the landscape of Marche that remains visible today. Monumental structures built along the great consular roads of Flaminia and Salaria testify to the strategic military importance of the region, while Roman amphitheaters, thermal baths, and triumphal arches survive in various states of preservation across numerous cities. The reform of Diocletian in 292 AD divided the territory between different administrative units, marking the beginning of an economic and social decline that would deepen through the turbulent centuries that followed the fall of the Western Roman Empire.