The Aachen Cathedral or Aachen Marienkirche, is the episcopal church of the diocese of Aachen and the most important landmark of the city of Aachen. The cathedral consists of several sub-buildings, their respective periods of origin include the era of the early Middle Ages to modern times. The Carolingian Oktogon, formerly the Palatine Chapel of the Aachener Königspfalz, is the most important architectural example of the Carolingian Renaissance. Charlemagne had the central building and the west building built at the end of the eighth century as the core of his palace. The laying of the foundation stone took place around 795, the completion around 803. The Carolingian Palatinate Church is surrounded by several additions from later times, including the Gothic choir hall in the east and the multi-faceted chapel wreath.