The Royal Palace, also known as the Norman Palace, was built by the Normans who invaded Sicily in 1072 . These are the descendants of the same Normans that crossed to England with William the Conqueror to defeat Harold at the Battle of Hastings in 1066. The former Islamic palace was chosen as their political centre and transformed into a royal residence and an administrative centre.

The Palantine Chapel was added in the 12th century.

It is a mix of Byzantine, Norman and Islamic architectural styles which reflects the impact of these cultural influences in Sicily at the time. It was commissioned by Roger II in 1132 and built on the site of an older chapel which now forms the crypt.

It took eight years to build and the mosaics were still unfinished in 1143.