Aachen (Holy City of Imperial Coronations for the Holy Roman Emperors)

Timeline

1. c. 768–814Aachen Palatium · Frankish EmpireCharlemagne exploited Aachen's hot springs and geographic position to build it into the permanent court of the Frankish Empire. Construction of the Palatine Chapel (today the octagonal core of Aachen Cathedral) began around 796, fusing Byzantine domed architecture with Frankish building styles; it became an iconic structure of the Carolingian Renaissance and around Christmas 800 witnessed Charlemagne's coronation as 'Emperor of the Romans' by Pope Leo III.
2. 936–1531Aachen Cathedral (Aachener Dom) · Holy Roman EmpireIn 936, Otto I of the Ottonian dynasty was crowned in Aachen Cathedral, inaugurating a tradition lasting over five centuries in which German kings of the Holy Roman Empire held their coronation ceremonies at Aachen. The coronation throne, the Karlsthron, became a sacred relic of imperial authority; emperors swore at the ceremony to protect the Church and preserve imperial unity. Ferdinand I's coronation in Aachen in 1531 was the last, after which the ceremony moved to Frankfurt.
3. 1618–1648Free Imperial City of Aachen · RhinelandAfter the outbreak of the Thirty Years' War in 1618, Aachen maintained relative autonomy as a Free Imperial City, but religious tensions between Catholic and Protestant citizens intensified amid the conflict. In 1621, Emperor Ferdinand II exploited the wartime situation to forcibly restore the dominance of Aachen's Catholic city council, expelling Protestant municipal officials—an act that drew diplomatic protests from Protestant powers including the Netherlands and England. The war obstructed trade, but Aachen's textile industry, especially its high-quality woolens, retained a certain scale under the protection of its neutral status.
4. 1668–1748Aachen · GermanyAachen served successively as the signing site of two major international peace treaties, in 1668 and 1748, reaffirming its symbolic status in European diplomacy. The 1748 Treaty of Aachen ended the War of the Austrian Succession and confirmed Maria Theresa's inheritance of the Habsburg lands, thereby securing Aachen an undeniable place in the history of European diplomacy.