The Palatine Chapel at Aachen is the most well-known and best-preserved Carolingian building. It is also an excellent example of the classical revival style that characterized the architecture of Charlemagne’s reign. The exact dates of the chapel’s construction are unclear, but we do know that this palace chapel was dedicated to Christ and the Virgin Mary by Pope Leo III in a ceremony in 805, five years after Leo promoted Charlemagne from king to Holy Roman Emperor. The dedication took place about twenty years after Charlemagne moved the capital of the Frankish kingdom from Ravenna, in what is now Italy, to Aachen, in what is now Germany.
In the construction of his chapel, Charlemagne made several strategic choices that linked his building to the legacies of ancient Rome and the fourth-century emperor Constantine. The Emperor Constantine was important because he was the first Christian emperor of Rome. The location for the new building was selected because it was an historic Roman site with hot springs that were used for bathing. The materials used for the chapel also invoked Rome; among them were columns and marble stones that Pope Hadrian permitted Charlemagne to transfer from Rome and Ravenna to Aachen around the year 798. A relic of the cloak of St. Martin was installed in the church at its consecration—the choice of a fourth-century Roman soldier who had a vision of Jesus after sharing his cloak with a beggar was another way to reinforce the link of Charlemagne’s rule with Rome.
The chapel’s classical style also referenced its Roman imperial lineage, particularly in its imitation of two significant Christian buildings: the Holy Sepulchre in Jerusalem and San Vitale in Ravenna. The faithful believe that the Church of the Holy Sepulchre in Jerusalem contains the site of the crucifixion of Christ and the tomb from which he rose. The Holy Sepulchre’s building program was started in 325 C.E. by Constantine’s mother, Saint Helena, and completed in 335. The centralized plan and surrounding ambulatory and upper gallery is echoed in the plan of the Palatine Chapel (the focus of a centrally planned church is at the center, in contrast to the more common basilica plan, that has a long hall; an ambulatory is the circular hallway outside a central space and a gallery is an open walkway looking onto a central space). However, the Holy Sepulchre in Jerusalem is composed of two main buildings—in addition to the rotunda that covers the tomb is a similar structure over the traditionally-accepted location of the crucifixion. The Holy Sepulchre may also have been the inspiration for the lion-head knockers of the chapel’s bronze doors (below).
Because it didn’t receive extensive additions like the Holy Sepulchre, the San Vitale Chapel at Ravenna is probably the best comparison for what the Palatine Chapel would have looked like before its Gothic renovations. San Vitale is a small octagonal church, with a centralized plan and a two-story ambulatory (below).
The octagonal plan of the Palatine Chapel (see plans above) not only recalled that of its two most significant models, but also participated in the tradition of early Christian mausoleums and baptisteries, where the eight sides were understood to be symbolic of regeneration—referencing Christ’s resurrection eight days after Palm Sunday. Its original dome was also based on classical models and bore an apocalyptic mosaic program, consisting of the agnus dei, or Lamb of God (which is, symbolically, Jesus Christ), surrounded by the tetramorph (symbols of the four Gospel writers) and the twenty-four elders described in Revelation 4:4. The agnus dei image was later obstructed by the installation of a chandelier.
The octagonal centralized plan of the Palatine Chapel is unique among Carolingian chapels; this may have been because, unlike a longitudinal plan which created a sense of processional direction toward the apse and altar, a centralized plan did not place special emphasis on the altar (and therefore may not have been as effective liturgically for the purpose of a chapel). That said, it does seem to have established an association of Charlemagne with Christ; some scholars believe that Charlemagne’s marble throne (below) was originally located in the center of the octagon on the first floor, that is, directly below the image of the agnus dei, thereby creating a kind of visual link between the emperor and the Christ.
By presenting his capital at Aachen as a new Rome and himself as a new Constantine through the careful appropriation of late antique artwork and architecture, Charlemagne was not simply making a positive assertion about himself as ruler; he was also implicitly contrasting his reign with that of the Eastern Empire (the Byzantines), a negative stance that was also expressed around the same time in the Opus Caroli Regis contra Synodum (i.e., “The Work of King Charles against the Synod), a detailed response to the Second Council of Nicaea, written on his behalf by Theodulf of Orléans (the Second Council of Nicaea was the last of seven councils recognized by both Orthodox and Catholic Christians).
Charlemagne’s body was interred in the Palatine Chapel after his death in 814. The building would continue to be used for coronation ceremonies for another 700 years—well into the sixteenth century.
Major additions to the chapel began in the fourteenth and fifteenth centuries, significantly changing the building’s profile and footprint with exterior chapels. After several fires in the seventeenth century, the dome was rebuilt and heightened.