The Castle of Guimarães was built under the orders of Mumadona Dias in the 10th century to defend the monastery from attacks by Moors and Norsemen. At the end of the 11th century the castle was heavily expanded and remodeled, under the direction of Count Henry, to act as his residence. The castle became the official royal residence from 1139, when Portugal became independent from the Kingdom of León, until circa 1200.
Between the end of the 13th and beginning of the 14th century, the castle was remodelled by King Denis, resulting in the form that stands to this day. In 1369, King Henry II of Castile invaded Portugal and encircled the castle of Guimarães, but was defeated by its population and forces. Sometime between 1383 and 1433, the two towers that flank the main entrance were order built by King John I of Portugal.
After the castle's demolition was abandoned in the 19th century, many of the houses, estates and lodgings around the castle were expropriated. The first attempts at restoration occurred during the mid-20th century.
Today Guimarães castle area is delineated by walls forming a pentagram, similar to a shield, that includes eight rectangular towers, military square and central keep. 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. It includes several Gothic characteristics, owing to its remodelling at the end of the 13th century, when the keep and residences were constructed (possibly over pre-existing structures).
References:Monte d"Accoddi is a Neolithic archaeological site in northern Sardinia, located in the territory of Sassari. The site consists of a massive raised stone platform thought to have been an altar. It was constructed by the Ozieri culture or earlier, with the oldest parts dated to around 4,000–3,650 BC.
The site was discovered in 1954 in a field owned by the Segni family. No chambers or entrances to the mound have been found, leading to the presumption it was an altar, a temple or a step pyramid. It may have also served an observational function, as its square plan is coordinated with the cardinal points of the compass.
The initial Ozieri structure was abandoned or destroyed around 3000 BC, with traces of fire found in the archeological evidence. Around 2800 BC the remains of the original structure were completely covered with a layered mixture of earth and stone, and large blocks of limestone were then applied to establish a second platform, truncated by a step pyramid (36 m × 29 m, about 10 m in height), accessible by means of a second ramp, 42 m long, built over the older one. This second temple resembles contemporary Mesopotamian ziggurats, and is attributed to the Abealzu-Filigosa culture.
Archeological excavations from the chalcolithic Abealzu-Filigosa layers indicate the Monte d"Accoddi was used for animal sacrifice, with the remains of sheep, cattle, and swine recovered in near equal proportions. It is among the earliest known sacrificial sites in Western Europe.
The site appears to have been abandoned again around 1800 BC, at the onset of the Nuragic age.
The monument was partially reconstructed during the 1980s. It is open to the public and accessible by the old route of SS131 highway, near the hamlet of Ottava. It is 14,9 km from Sassari and 45 km from Alghero. There is no public transportation to the site. The opening times vary throughout the year.