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Architecture and history of the building

Architectural history

The Carolingian St Mary’s Church was built on the remains of a Roman thermal complex and on the site of a Merovingian chapel. The altar of St Mary’s Church was placed in the same position it had in the Merovingian chapel; only its orientation was changed. It was turned 38 degrees in an easterly direction. In shape and size, it surpassed all churches built north of the Alps up to that time. The Frankish ruler brought experts from all over the empire to Aachen to realise the immense project. Odo of Metz is said to be the architect. The floor plan is based on a system of measurements referring to the Book of Revelation. The Palatine chapel (Hochmünster) forms the central building of the Cathedral. The west building and the Octagon in the centre have been preserved to this day.

The Choir hall

The increased use of the church by pilgrims led to the extension of the Cathedral from 1355 onwards. The Gothic choir hall (completed in 1414) is 25 metres long, 13 metres wide and 32 metres high. Its outer wall consists mostly of windows. At 25.55 m, the windows of the Choir are some of the largest Gothic windows in Europe. The glass has a total area of more than 1,000 m², giving the Choir hall the nickname “Glass House of Aachen”.

The great city fire

In 1656, the great fire of Aachen severely damaged the church: the roofs and the tower, including the bells, were destroyed. The difficult financial circumstances of the church and the city of Aachen only allowed for a temporary restoration.

The baroque period

With Aachen’s revival as a renowned spa town, a late phase of “baroqueisation” began in the 18th century. The Carolingian Octagon was decorated with stucco in the style of the time, the Choir windows lost their Gothic traceries and the neglected Chapel of Hungary was rebuilt.

During the French period – Aachen was occupied by French troops in 1794 and belonged to France from 1801 to 1815 – the Minster was raised to the status of Cathedral Church of the first Diocese of Aachen (1802-1827). At the same time, it suffered severe damage from looting, such as the removal of the 32 ancient columns from the Hochmünster and the dismantling of all the lead roofs.

Restoration in the 19th century

The restoration of Aachen Cathedral in the 19th century brought about major changes to the building. The Gothic parts of the Cathedral were extensively restored, and a neo-Gothic west tower was erected over the Carolingian west building in 1884.

The Byzantine-like interior decor of the Carolingian building is an impressive culmination of this period. Based on a drawing from 1699, painter and architect Baron de Béthune created the design for the restored mosaic on the dome which was completed in 1881 and depicts the enthroned Christ and the twenty-four elders surrounding him.

The cladding of the pillars and walls with marble and the decoration of the tambour walls and the ambulatory vault with mosaic were carried out between 1900 and 1913 and were designed by the artist Hermann Schaper. After Schaper’s sudden death, his successor Friedrich Schwarting completed the work with financial support from the German Emperor Wilhelm II.


From the founding period of the cathedral

24 antique columns set as the architectural decoration of the High Minster
Eight Carolingian bronze grilles
Two small double-wing bronze doors
The monumental bronze doors of the main entrance

Important testimonies of pilgrimages and veneration of saints

The Charlemagne Shrine (c. 1182-1215)
The shrine of the Virgin Mary, completed in 1238

The Choir Hall