The customshouse was constructed in 1325 by royal decree on top of a Roman villa. References to the Casas da Alfândega in the next two years, suggest that it had already been completed and in use. The mediaeval customshouse began being built around 1354 in the reign of King D. Afonso IV, would likely have been born here: the customshouse was the only royal building in the city and that it had living quarters for the royal employees, it is likely that the Cortes occupied the building at that time of his birth. This would confirm a long-held oral tradition. At the end of the 14th century, was the first reference to the Portuense Casa da Moeda during the reign of King D. Fernando I, that allowed dating of the open space in the principal entrance. In 1587, was the last reference to the work on the Casa da Moeda, but a few years later, a royal letter extinguished the institution. In 1628, there were new references to work in the old House of Coin. The Finance inspector issued an order in 1656 to move the customshouse to the remnants of the House, and to promptly complete its reuse; starting in the 15th century, the customshouse underwent several expansions and re-modellings that altered its original structure. The most important remodelling occurred in 1677, under the reign of King D. Peter II, when the building was virtually rebuilt. The inner courtyard was kept, but the towers were greatly reduced in height, while the front of the building gained two extra storeys, with a large staircase leading to the living quarters in the second floor. The front of the building incorporated the functions of the towers and the storage rooms were greatly enlarged. A commemorative inscription, dated 1677, refers to this change: In 1860, the work and construction of the new customshouse in Miragaia, wherein the services were gradually transferred to the new site. In 1894, a new Neo-Manueline plaque was installed on the principal entrance, commemorating the birth of the Infante D. Henrique. The building was re-constructed in 1923, that saw the building obtain a new floor over the principal facade. Between 1957 and 1978, the DGEMN Direção-Geral dos Edifícios e Monumentos Nacionais began a series of projects to recuperate and remodel the old customs house. Beginning with surveys and excavations, there were a series of works to restore and consolidate the structure. In 1960, upgrades to the electrical systems and the installation of new lighting highlighted further work on the reinforced concrete pavements. This included supply and placement of wood on the ceiling and halls of the central patio, concrete staircases, work on the windows, sanitation and drainage of the spaces, as well as complementary restoration of the walls, stone slabs and facades. In 1991, the beginning of work to transform the house into the Arquivo Histórico Municipal do Porto, that included an initial phase of archaeological intervention under the responsibility of Manuel Luis Real and archaeologists Paulo Dordio Gomes and Ricardo Teixeira. They discovered vestiges of a large Roman foundation, remains of a mosaic pavement. The second phase of the project, under the direction of Nuno Tasso de Sousa, to transform the interior and exterior to serve its needs: it now houses an exhibition of the history of Porto, including a scale model of medieval Porto, and the supported by a .
Architecture
The Casa do Infante is addorsed to buildings in the historic centre of the city, along the riverbank, with its principal facade oriented to the inclined slope descending the Praça do Infante D. Henrique towards the Largo do Terreiro and access to the Cais da Estiva along the Douro. The plan consist of four rectangular, juxtapositioned articulate spaces covered in differentiated of articulated ceiling tiles. The principal facade consists of four storeys covered in canopy windows. On the right-side of the first floor is a large arched doorway, surmounted by the royal coat-of-arms and a 1677 inscription, while the rear corps are uniformly lower. From the entrance is the access to a framed patio surmounted by archway framing the two upper floors, a large door that connects it to the rest of the buildings bodies, towards the east. The first of these buildings is a large space of three naves defined by high arcade. Along its continuity, the buildings have two storeys accessible from the central nave by a staircase. In the rear facade are a series of high windows that illuminate the pavement and patio involving the eastern and northern buildings. From here are accessways to Rua Infante D. Henrique across a ramp and tunnel, that opens to an archway surmounted by royal coat-of-arms. Alongside the door exists a stone with the shield of the Avis dynastic family. Archaeological excavations since 1995 identified a group of structures buried in the entirety of the property, allowing the reconstruction of the medieval organization of the customhouses and "House of Coin", with vestiges of an early Roman construction of grand dimensions, with polychromatic mosaics.
