The Palau de Fluvià, known as Obra de Fluvià, is located one kilometre away from Guissona, next to the road that leads to Biosca, in the old territory of the Fluvià village. The site, which had belonged to the university of Guissona since 1383, eventually came under the jurisdiction of the bishopric of Urgell. In 1505, the bishop Peter of Cardona bought all of the state rights and began the construction of a residence-palace for the bishops of Urgell, replacing the old castle.
The work advanced quickly, but was interrupted in 1514, when the bishop Cardona moved to Tarragona as the new metropolitan archbishop. At that time, the ground floor was finished and covered.
It is a Gothic-Renaissance palace which was left unfinished at the start of the 16th century. The construction is of square plant, centred by a courtyard, from which all rooms unfold. The church of the palace is one of the most interesting spaces of the ensemble and was consecrated to Saint George, Saint Lucy and Saint Blaise. The main façade has three opening on the right side, two of which are windows with arcades held by corbels with vegetal and zoomorphic motives, and the third one has and oeil-de-boeuf. All three windows preserve Gothic decoration with segmental arches and pronounced mouldings. On the left side of the façade, all openings are currently mortared and one can see a very deteriorated window and a door, which gave direct access from the outside to the church. On the east façade, there are several openings, all mortared of unfinished and a door that is connected to the stables. One can access the palace through a foyer that leads to a richly decorated hall on the right and to the church on the left; in front, as previously stated, there’s a courtyard that centralises the whole building.
Some mouldings, friezes decorated with vegetal motives, filigrees, voussoired arches that provide access to the rooms, relieves with vegetal motives, richly decorated capitals, etc.
In 1808, with the Peninsular War, the French fortified the building and demolished part of the roof.