 It is the best-preserved medieval royal residence in Portugal, being inhabited more or less continuously from at least the early 15th century to the late 19th century.It is a significant tourist attraction, and is part of the cultural landscape of Sintra, a designated UNESCO World Heritage site.It was one of two castles at what is now Sintra in the Moorish Al-Andalus era that began with the Umayyad conquest of Hispania in the 8th century.