Originally, the Castle of Sintra was built by the Moors, possibly between the 9th and 10th centuries. Arab chronicles depict the Sintra region as being very rich in cultivated fields. Its castle was one of the most important in the surroundings and served as an excellent observation point for monitoring the coast as you can see in the picture above. In 1109, the castle became subject to an attack by crusading Norwegians, led by King Sigurd I, on their way to the Holy Land. Every man at the castle was said to have been killed as they had refused to become christened.