[1] The castle is a military fortification grounded primarily in the late Romanesque period, and elaborated during the early Gothic epoch of Portuguese architecture.

Originating in the foundations of a Roman structure, from the writings of Alfredo Guimarães, it was later elaborated on the French model, in its current the form of a shield, with reduced central yard and difficult accesses.

[2] The examination of its walls and remains led Carlos A. F. de Almeida to proclaim, for example, that the flanking towers were constructed during the late Romanesque, early Gothic period.

[2] In the second half of the 10th century, owing to the death of Count Hermenegildo Gonçalves, the property of Vimaranes (today Guimarães) was inherited by his daughter Oneca.

[2] At the end of the 10th century, Dias's eldest son, Gonçalo Mendes, takes possession of the lands following her death and maintaining her wishes to support the monastery.

[2] Following years of family rivalries, in 1128, the Battle of São Mamede (fought within the fields of the same name) gave origin to the independence of Portucale and the formation of the nucleus of what would become Portugal.

[2] In 1369, King Henry II of Castile invaded Portugal and encircled the castle of Guimarães, but was defeated by its population and forces loyal to then-alcaide Gonçalo Pais de Meira.

[2] Yet, several years (1385) King John I encircled the castle, and it was the alcaide Aires Gomes da Silva, supporter of Beatriz, who defended its walls.

45 years later, on 19 March 1881, the Diário do Governo (Official Journal) listed the Guimarães Castle as the most unusual historic monument of the whole region of Minho.

[2] In the vicinity, on the hillside, is the Romanesque church of São Miguel do Castelo (PT010308340006), the Palace of the Dukes of Braganza (PT010308340013) and some sections of wall (PT010308340016) that surrounded the city, and that were originally integrated into the castle.