much earlier phase. Around AD 1000 the population probably moved towards the more easily defensible hill-site of Montecchio (later called Treia) and the original town site remained practically deserted. The town sided with the Pope in the temporal struggles of central Italy, and was besieged several times, and in particular in 1239 by Enzio, son and vicar of Frederick II and again in 1263 by Conrad of Antioch, who was captured at the nearby battle of Vallesacco, and held for several months in town in a small prison (now in use as a caffé). Montecchio eventually became part of the Papal States, and in 1790 Pope Pius VI rewarded it for its faithfulness by raising it to the official rank of "city", at the same time renaming it by its Roman name of Treia. Treia's most famous native was the archaeologist and art critic Luigi Lanzi. Archaeology From 2000 onwards the Potenza Valley Survey Project, a project of Ghent University directed by Frank Vermeulen, attempts to map all buried structures of the ancient town. The survey methodology involves a series of aerial photography operations, large-scale geophysical prospections and intensive artefact surveys and studies. Due to all this new information it is now possible to map most parts of the town’s infrastructure in detail. Roman Trea was situated along an important byroad of the via Flaminia, which connected Rome directly to the harbour city Ancona, via most of the Potenza Valley. Around this road a street-side settlement developed gradually into a real town during the Late Republic. The town wall delimiting the main urban area has an irregular oval shape, which agrees well with the general topographic configuration of the hilly plateau. The total enclosed area is only about 11 ha but possibly extramural habitation areas existed, particularly on the eastern and western sides. The street grid, individuating insulae of different size, is organized parallel with and perpendicular to a central decumanus maximus. Centrally the main road is interrupted by the monumental forum complex. The open rectangular square, is bordered by porticoes, tabernae and a series of public buildings. Centrally on the eastern side stood a rectangular building identified as the main podium temple. On and near the short west side of the forum stood a basilica, and possibly a curia. The planned forum was probably constructed in late Republican and early Imperial times. The remnants of another temple, discovered under