Afonso, Count of Barcelos, was the illegitimate son of King John I of Portugal. Between 1420 and 1422, returning from diplomatic missions that had taken him through the grand courts of France, Venice, Aragon, and Castile, he ordered construction of a palace in Guimaraes that would reflect the architectural sophistication he had seen abroad. Some scholars attribute the design to a French architect named Antom. The building marked the beginning of Afonso's second marriage and his decision to establish a permanent residence in the town. The palace was still under construction in 1442, when the Regent Peter visited and conferred on Afonso the title of 1st Duke of Braganza -- transforming an illegitimate son into the founder of a dynasty that would eventually rule Portugal, and later Brazil.

The palace is built around a rectangular plan with four corner towers enclosing an interior courtyard, dominated by the chapel on the southeast wing. Six tall chimneys rise from the roofline, a distinctive silhouette visible across the city. The granite facades are punctuated by windows in varying styles -- cruciform, stained glass, standard, and oblique -- reflecting the different phases and influences of its construction. The interior courtyard features Gothic arches on the main floor and columns on the second, with granite-corbeled balconies running along every interior facade. The chapel, identifiable from outside by its two large Flemish stained-glass windows, extends from the southwest wing and is reached through a portal of four inset arches preceded by a staircase. The Banquet Hall and the evocatively named Hall of Lost Steps feature wooden ceilings shaped like the inverted keel of a ship, a design that gives the rooms an unexpected maritime grandeur.

The Braganza dynasty's move to Vila Vicosa in the 16th century marked the beginning of the palace's long decline. Without its noble residents, the building deteriorated rapidly. The 19th century brought active destruction, as townspeople repurposed its worked stone for humbler projects. By the early 20th century, old engravings show a structure reduced to walls and shadows, its interiors open to the sky. The palace was classified as a National Monument in 1910, but salvation came in a controversial form. Under the Estado Novo regime, a sweeping restoration rebuilt the palace to a grandeur that historians debate ever existed. The reconstruction implied a magnificence that may have owed more to 20th-century nationalist ambitions than to 15th-century reality. Nevertheless, the restored palace became an official presidential residence, its top floor fitted with suites for the President and Prime Minister, accessible by elevator.

Today the palace serves a triple purpose: museum, presidential residence, and symbol. The first floor houses reception areas, storage spaces, and administrative offices. The intermediary floor is open to the public as a museum, its halls displaying period furniture, tapestries, and artifacts within rooms warmed by massive stone fireplaces. The chapel retains its single nave covered by a wooden ceiling with visible joists, its richly carved benches preceding an elevated presbytery. Walking through the palace is an exercise in reading layers of time -- the 15th-century proportions, the 20th-century reconstruction, the museum installations, and the presidential quarters that ensure the building remains a working seat of government. The palace sits on the hillside below the Castle of Guimaraes, within a protected heritage zone established in 1952 that links it to the castle and the Romanesque Church of Sao Miguel. Together, these three monuments tell the story of Portuguese power from medieval fortress to ducal grandeur to modern republic.