The Aachen Cathedral, frequently referred to as the "Imperial Cathedral" (in German: Kaiserdom) of Aachen, is the oldest cathedral in northern Europe. Charlemagne began the construction of the Palace Chapel in 786. When he died in 814, he was buried in his own cathedral, and his bones are still preserved in a special shrine.
The cathedral obtained its present shape in the course of more than a millennium. The core of the Aachen cathedral is the Palace Chapel; being surprisingly small in comparison to the later additions, at the time of its construction it was the largest dome north of the Alps. Its fascinating architecture with Classical, Byzantine and Germanic-Franconian elements is the essence of a monumental building of great importance: for 600 years, from 936 to 1531, the Aachen cathedral was the church of coronation for 30 kings of the Holy Roman Empire.
In order to bear the enormous flow of pilgrims in the Gothic period a choir hall was built: a two-part Capella vitrea (glass capel) which was consecrated on the 600th day of Charlemagne's death.
Ever since, the magnificent architecture of the "glass house" of Aachen has never stopped being admired. In 1978, it was one of the first 12 items to make the entry into the UNESCO list of world heritage sites, as the first German and one of the first three European historical ensembles.
The Aachen cathedral treasury displays sacral masterpieces of the late Classical, Carolingian, Ottonian and Staufian period - among them there are some unique exhibits like the "Cross of Lothair" the "Bust of Charlemagne" and the "Persephone sarcophagus". The Cathedral Treasury in Aachen is regarded as one of the most important ecclesiastical treasuries in northern Europe.
In 1001, Otto III had Charlemagne's vault opened. It is said that the body was found in a remarkable state of preservation, seated on a marble throne, dressed in his imperial robes, with his crown on his head, the Gospel's lying open in his lap, and his sceptre in his hand. A large picture representing Otto and his nobles gazing on the dead Emperor was painted on the wall of the great room in the Town Hall.
In 1165, Emperor Frederick Barbarossa again opened the vault and placed the remains in a sculptured sarcophagus made of Parian marble, said to have been the one in which Augustus Caesar was buried. The bones lay in this until 1215, when Frederick II had them put in a casket of gold and silver.