The castle stands on the hill in the centre of the old town, overlooking and dominating all its historic buildings. Of enormous strategic importance, the fortifications and the views they offer of the town and its surrounding area are stunning. It is an unparalleled vantage point and a marvellous viewpoint over Tortosa.Iberian and Roman remains have been found there. The Arabs fortified it in the time of Abd-al-Rahman III, and it was a royal residence from the time of King James I of Catalonia onwards. In general terms, its perimeter has remained the same, determined by the features of the terrain. Originally, square defensive towers seem to have alternated with sections of wall. Over the centuries the structure had to be adapted to meet new military demands, replacing battlements and towers with embrasures and parapets. In the 17th and 18th centuries, bastions were built at the north-eastern end.