Charlemagne's favourite residence and burial place, whose Palatine Chapel became the coronation church of thirty-one German kings between 936 and 1531 and one of the great pilgrim shrines of the late Middle Ages.
Aachen lies near the modern borders of Germany, Belgium and the Netherlands, in a valley of hot springs that the Romans used as a spa called Aquae Granni. In the 790s Charlemagne chose it as the permanent seat of his court, and the palace he built there turned a minor spa into the political centre of the Carolingian empire.
The town's importance outlived the empire that created it. Charlemagne was buried in his Palatine Chapel in 814, and for more than six centuries German kings came to be crowned on his stone throne there, claiming his inheritance. The octagonal chapel survives at the heart of Aachen Cathedral, which in 1978 became the first German site on UNESCO's World Heritage List.
Pepin the Short had already spent a winter at Aachen in 765, but it was his son who transformed it. From about 794 Charlemagne spent most winters there, and the scholars of his court, among them Alcuin of York and his biographer Einhard, made it the centre of the Carolingian revival of Latin learning. Einhard says the king loved the hot springs and swam in them with his sons, nobles and bodyguards, sometimes a hundred men at a time.
The palace complex was laid out on a grid: a great audience hall to the north, on whose foundations Aachen's Gothic town hall now stands, linked by a covered gallery to the Palatine Chapel to the south. The chapel, designed by Odo of Metz and consecrated around 805, is an octagon inside a sixteen-sided ambulatory, modelled on the imperial churches of Ravenna, and Charlemagne obtained Pope Hadrian I's permission to bring columns and marble from Ravenna and Rome to build it.
Aachen was also where the Frankish church and empire were reshaped. A synod there in 809 defended the Frankish addition of the filioque to the creed, envoys of the Byzantine emperor acclaimed Charlemagne as emperor at Aachen in 812 in the settlement that ended his war with Constantinople, and under Louis the Pious the councils of 816 and 817, guided by Benedict of Aniane, imposed the Rule of Saint Benedict on the monasteries of the empire.
At Aachen in 813 Charlemagne crowned his son Louis the Pious co-emperor himself, without a pope, and there he died on 28 January 814 and was buried in the chapel the same day. His heirs used the palace less, and in 881 Viking raiders from the Rhine valley sacked it.
The Ottonians revived Aachen as a symbol. Otto I was crowned king in the Palatine Chapel in 936 and seated on the stone throne in its gallery, and the ceremony became the rule: thirty-one German kings were crowned at Aachen before the last, Ferdinand I, in 1531. In the year 1000 Otto III opened Charlemagne's tomb; a later chronicle claimed he found the emperor seated upright on a throne, a story historians treat as legend. The throne itself, plain marble slabs raised on six steps, may date from Charlemagne's own time, and the cathedral treasury still holds gifts of later rulers, among them the Lothair Cross of about 1000 and the gilded pulpit given by Henry II.
In 1165 Frederick Barbarossa had Charlemagne canonised by his antipope, Paschal III, and the next year granted Aachen a charter of liberties. His grandson Frederick II, crowned there in 1215, closed the new gold shrine over Charlemagne's bones with his own hands. Aachen grew into a free imperial city governed by its own council, and the Golden Bull of 1356 fixed it in law as the place where kings of the Romans were to be crowned.
Aachen's townspeople turned royal favour into self-government. Barbarossa's charter of 1166 gave the town its own peace and market privileges, and by the thirteenth century a council of aldermen and burgomasters governed both the city and the surrounding villages known as the Aachen Realm. From about 1330 the council built its town hall on the foundations of Charlemagne's audience hall, and in 1349 the coronation banquet of Charles IV was the first held in its great hall.
The town lived by cloth and metal. Aachen weavers made woollens for export through Cologne and the Low Countries, and the calamine ore mined in the nearby hills fed the copper-alloy workshops whose brass vessels and fittings were sold along the Rhine.
Aachen's relics made it one of the great pilgrim cities of the late Middle Ages. From 1349 the four great relics, venerated as the cloak of the Virgin, the swaddling clothes and loincloth of Christ, and the cloth that received John the Baptist's severed head, were shown every seven years, and tens of thousands of pilgrims from Hungary, Bohemia and the Low Countries crowded the town. Pilgrims held up small convex mirrors to catch the blessing of relics they could not get close to, and Johannes Gutenberg's first recorded business venture, in the late 1430s, was a partnership to make such mirrors for the Aachen pilgrimage.
To receive the crowds, the town rebuilt its most famous building. The Gothic choir, a tall 'glass house' of windows added to the Carolingian octagon between 1355 and 1414, housed Charlemagne's shrine. A double circuit of walls, the inner twelfth-century ring and an outer wall of the thirteenth and fourteenth centuries with its gates, enclosed a town that lived from pilgrims, cloth-making and the copper and brass working of the surrounding valleys.