Ulmetum is the name of the ancient Roman settlement on the outskirts of the village Pantelimonul de Sus, as it results from an inscription in which were mentioned the inhabitants “civi romani et Bessi consistenses in vico Ulmetum” (Romani citizens and bessi consistenti from the village of Ulmetum).
According to historical sources, the fortress was built around the 3rd century AD, during the late Roman period and lasted until the sixth century, during the Roman-Byzantine era. It was a small fortress, which gradually became a fortified settlement and which in the 5th century was almost destroyed by three attacks from the Huns.
The ancient settlement of Pantelimon had the form of a rectangular triangle with a curved hypotenuse. On the corners ,the fort was provided with three round towers. It had two gates flanked by two towers with a semicircular front side (in the form of the letter U). On the side of S-E (hypotenuse), there are 4 rectangular towers, to which are added two towers of the same shape, one on the other two sides of the fortress. The defense wall at Ulmetum was 2.60 m thick, the foundation being 20 to 60 cm wider than the elevation. In the surveys conducted by Vasile Parvan, the foundation had a depth of 1.85 m to 2.50 m.
The walls were plastered with reused stone blocks on the outside, their dimensions reaching 2.70m (a funerary star). Inside the enclosure ,there are no wall blocks. There are also traces of stone stairs that allowed to climb the wall, the steps having the height between 28 cm and 40 cm, and the width up to 1m.