I can’t imagine writing anything that would supplement the huge volume of admiration for this building at your fingertips online. So, for your convenience here’s an excerpt from one of my favorite sites culturetrip.com;
The ‘Reales Alcázares de Sevilla‘, as it is known in Spanish, is a royal palace which was built by the Moorish rulers who occupied the peninsula from the 8th century onwards. In the 13th century, the Spanish Reconquista was in full swing and the Catholic Kings of Spain claimed the palace as their own. This marks the beginning of a new era for the palace, one under which elements of Gothic, Renaissance and Romanesque design were combined to the original Islamic structure, leading to the unique blend of styles known as Mudéjar.
It is by and large considered to be one of the most outstanding examples of mudéjar art to exist today.