Assisi began having diplomatic relations with Rome in III century B.C.
It entered a treaty of cooperation by accepting to provide military contingents. In 90 B.C. it became a Roman Municipality. After 41 B.C. part of its territory was confiscated and assigned to the nearby town of Spello. In those same years Properzio, one of the best elegiac poet of the time, was born in Assisi.
The archaeological collection pertaining to the municipality is in the Museum of the Roman Forum, partly housed in the Crypt of San Nicolò, and also extends on the surface underneath the square until it reaches a room where it is possible to see the paved floor of the south area of the ancient Forum.
Assisi’s prosperity under the Roman Empire is clearly evident not only in the Roman Forum but also in the Temple of Minerva, the Amphitheatre (in the top part of the town) and the Domus (Roman Domus of Palazzo Giampè and Casa Romana said to be Properzio’s).