Around 15 BC the Roman camp Castra Vetera was created on the Fürstenberg near modern-day Birten. It was intended as a base for campaigns into Germania and until its destruction during the Revolt of the Batavi in 70 AD it was occupied by 8,000 to 10,000 legionaries, and was the main base of the Classis germanica.

After the destruction of Castra Vetera a second camp became established at the Bislicher Insel, named Castra Vetera II, which became the base camp of Legio VI Victrix. A nearby created settlement, which was inhabited by 10,000 to 15,000 former legionaries and others, was given the rights of a colonia in 110 by the Roman emperor Marcus Ulpius Traianus, who renamed the city Colonia Ulpia Traiana. The colonia was a completely new city with a city wall and other buildings like an amphitheater. For this city the old settlement was destroyed completely. The colonia became the second most important commercial post in the province of Germania Inferior, surpassed only by Colonia Agrippinensis (today’s Cologne). In 122, Vetera II became the camp of Legio XXX Ulpia Victrix, replacing VI Victrix which had moved to Britannia.

In 275 the colonia was almost destroyed by Germanic tribes. Subsequently, in AD 310 in the area of the colonia a new city was established, named Tricensimae (“of the Thirtieth”), which was built on the nine central insula of the former colonia but fortified and more easily defended. At the beginning of the 5th century, assaults by Germanic tribes rapidly increased, with the result that Tricensimae was finally given up.

In 1975, the Archäologischer Park Xanten (Xanten Archaeological Park), a partial reconstruction of the Roman Colonia Ulpia Traiana, was established and opened for tourism. It is built on the site of the Roman town. Today it is one of the most frequently visited parks in Germany. Among other events there, even the popular TV show Wetten dass..? has taken place in the APX. In 2012, the Archaeological Park was expanded to nearly the whole area of the Roman Colonia after the Bundesstraße 57 moved away from the middle of the area.