Maastricht's prehistory (up until around 50 BC) saw the first traces of human activity in the area, dating back to around 300,000 BC with the discovery of a hunters' camp in the Belvédère grove in Oud Caberg.
Other traces from the area's younger prehistory have also been found in Oud Caberg, as well as on the other side of the Maas in Heugem and elsewhere. The arrival of the Romans put an end to Maastricht's prehistory, and they encountered Celts upon their arrival. The Romans built a sanctuary on the present-day Onze Lieve Vrouweplein and constructed a military road from Boulogne on the French coast to Cologne, passing through Maastricht and crossing the Maas via a ford and later a bridge, which was renovated in 250 AD. A castrum near the present-day Onze-Lieve-Vrouwekerk protected the bridge. Christianity appeared around 150 AD, and in the fourth century, Bishop Servaas came to Maastricht from Tongeren, where he died on an unknown date and was buried along the road. Little is known about the years between the departure of the Romans and the eleventh and twelfth centuries, but Maastricht became part of the Frankish empire. It had a harbor, a tollbooth, and a mint. It was also home to a bishop, likely in the Onze-Lieve-Vrouwekerk, which was built in the late sixth century. Known bishops from this period include Amandus, Lambertus, and Hubertus. The latter moved the seat to Liège in the eighth century. This period also saw the formation of the chapters of Onze Lieve Vrouwe and Sint Servaas. In the eleventh and twelfth centuries, Sint Servaas became a German imperial chapter closely associated with the German emperors, while Onze Lieve Vrouwe became a Liège chapter dependent on the bishop. The settlement on the Maas was characterized by its dual nature, with parts being Liège and parts being imperial. In 1202 and 1204, the German empire ceded its rights to the Sint Servaas chapter and the settlement of Maastricht to the Duke of Brabant. During the late Middle Ages (1200-1500), Maastricht grew into a self-governing city-state thanks to its dual nature as outlined in the Alde Caerte (1284). Although the city was never officially elevated to the status of a city, the right to fortify it (granted in 1229) was the visible sign of its autonomy. The city's government represented the authority of both lords, not that of the people. The driving forces behind the city at this time were the guilds, but they struggled to gain control over the city's administration. The city was also a center of trade, manufacturing, and the cloth industry, and it was surrounded by a large number of small and medium-sized cities. The city's prosperity continued until the fifteenth century, when it was hit by a number of disasters, including the Black Death and a series of wars. The city's decline continued into the sixteenth century, exacerbated by the Protestant Reformation and the Eighty Years' War.
