In Frankfurt Roman settlements were established in the area of the Römer, probably in the 1st century. Nida (Heddernheim) was also a Roman civitas capital. Alemanni and Franks lived there and by 794 Charlemagne presided over an imperial assembly and church synod, at which Franconofurd (-furt -vurd) was first mentioned.
Frankfurt was one of the most important cities in the Holy Roman Empire. From 855 the German kings and emperors were elected and crowned in Aachen. From 1562 the kings and emperors were crowned in Frankfurt, initiated for Maximilian II. This tradition ended in 1792, when Franz II was elected. His coronation was deliberately held on Bastille Day, 14 July, the anniversary of the storming of the Bastille. The elections and coronations took place in St. Bartholomäus Cathedral, known as the Kaiserdom (Emperor's Cathedral), or its predecessors.
The Frankfurter Messe (Frankfurt Trade Fair) was first mentioned in 1150. In 1240, Emperor Friedrich II granted an Imperial privilege to its visitors, meaning they would be protected by the Empire. The fair became particularly important when similar fairs in French Beaucaire lost attraction around 1380. Book trade fairs began in1478. In 1372 Frankfurt became a Reichsstadt (Imperial Free City), i.e. directly subordinate to the Holy Roman Emperor and not to a regional ruler or a local nobleman.
In 1585 Frankfurt traders established a system of exchange rates for the various currencies that were circulating to prevent cheating and extortion. Thus lay the early roots for the Frankfurt Stock Exchange. Frankfurt managed to remain neutral during the Thirty Years' War, but suffered from the bubonic plague that refugees brought to the city. After the war, Frankfurt regained its wealth.