Iesso, located in the present-day town of Guissona, is one of the few Roman cities in Catalonia on which the present-day city has not been completely superimposed. This gives it considerable archaeological potential. In addition, it is one of the most well-documented examples of urban activity that unfolded in Catalonia in 100 BC: a crucial historical moment in which the urban network inherited by our current cities, began to be constructed.

Ancient Iesso was an important inland capital of the empire. About 20,000 people lived there and it occupied twice as much ground as Barcino. In Roman hands, the city experienced 700 years of prosperity, based on agriculture and intense commercial activity. The original town was surrounded by walls and the streets arranged around two axes, the cardo maximus, on a north-south orientation, and the decumanus maximus, running from east to west, following the usual urban plan of Roman cities.

The constructive and commercial activity of Iesso continued up to the Visigothic period (6th century), even though the period that followed the dissolution of the Roman Empire in Guissona was a historic moment of unknown force.

Nowadays, the Archaeological Park of Iesso offers the perfect example in which to discover the development and the transformation of the Roman city over time. Notable are the large public baths, with an advanced system for the circulation of water, the remains of a facility to produce wine and a large manorial house organised around a central courtyard.