The Countess Mumadona Dias had two constructions of great importance built in Guimarães in the 10th Century, the two cornerstones of the origins of the city: the Monastery of Santa Maria and the Castle of S. Mamede, thus named in Mumadona’s will.

As the historian Mário Jorge Barroca mentions, the 10th century castle should be very different from the one we know today, for the works were incipient , turrets were rare and keeps were unknown, whereby it was often necessary to resort to the removal of lands to create accentuated unevenness.

The Castle was object of numerous alterations, whereby its current configuration has little to do with its original form.  In fact, with Count Henrique some interventions were carried out and, according to Mário Barroca, there are traces that one supposes are from the time of this Count.  Later, in the 13th or 14th centuries, with King Dinis, the Keep was built as well as the eight turrets that flank the castle.

Other later reforms were undertaken during the reign of João I, whereby its last form was then defined.

The fact that the Guimarães Castle was the first Portuguese castle to have photographic records that show us the structure such as it was in the 19th century is also interesting.  These photographs are from Frederick William Flower, an English trader that lived in Porto for a few years, which was the pioneer in the usage of Photography.

After centuries of abandonment and ruin, the Castle went through restoration, undertaken during the 1930s by the DGEMN.  The objective of these upgrading works was to rehabilitate the most emblematic site of national castleology.

The Guimarães Castle is a National Monument since 1910 and one of the 7 Wonder of Portugal since 2007.