One of Palermo's oldest churches, Chiesa della Martorana was originally built in a quadrangular form based on the stile of current Byzantine churches under the reign of King Ruggero II. It underwent various modifications in the same century in which it was founded, and its embellishments included a wonderful atrium decorated with spectacular mosaics, a baptismal fountain of Greek custom and a magnificent bell tower. However, the most important and substantial intervention occurred during the Baroque era, (between the end of the 16th Century through the 17th Century), when the church was lengthened. This involved destroying the original facade and the internal narthex; the atrium was covered, the central apse was demolished and the the current facade and chancel were built. The internal structural elements and the Norman and Baroque decorations are worth admiring.