Coronation of the Holy Roman Emperor in the context of "Prince-elector"

Frankfurt am Main, commonly referred to simply as Frankfurt, is the most populous city in the German state of Hesse. Its 778,589 inhabitants as of 2025 make it the fifth-most populous city in Germany. Located in the foreland of the Taunus on its namesake Main, the city forms a continuous conurbation with Offenbach am Main; its urban area has a population of over 2.7 million. Frankfurt is the heart of the larger Rhine-Main metropolitan region, which has a population of more than 5.8 million and is Germany's second-largest metropolitan region after the Rhine-Ruhr region. Home to the European Central Bank, the city serves as one of the four institutional seats of the European Union (alongside Brussels, Luxembourg and Strasbourg). Frankfurt is classified by the GaWC as an Alpha-rated world city.

Frankfurt was a city state, the Free City of Frankfurt, for nearly five centuries, and was one of the most important cities of the Holy Roman Empire, as a site of Imperial coronations; it lost its sovereignty upon the collapse of the empire in 1806, regained it in 1815 and then lost it again in 1866, when it was annexed (though neutral) by the Kingdom of Prussia. It has been part of the state of Hesse since 1945. Frankfurt is culturally, ethnically and religiously diverse, with half of its population, and a majority of its young people, having a migrant background. A quarter of the population consists of foreign nationals, including many expatriates. In 2015, Frankfurt was home to 1,909 ultra high-net-worth individuals, the sixth-highest number of any city.

The election of a Holy Roman Emperor was generally a two-stage process whereby the King of the Romans was elected by a small body of the greatest princes of the realm, the prince-electors. This was then followed shortly thereafter by his coronation as king, originally at Aachen and later at Frankfurt. The king was then expected to march to Rome, to be crowned Emperor by the pope. In 1356, the Emperor Charles IV promulgated the Golden Bull, which became the fundamental law by which all future kings and emperors were elected. After 1508, rulers usually were recognized as "Emperor elect" after their first, royal coronation.

Pope John XII (Latin: Ioannes XII; c. 930/937 – 14 May 964), born Octavian, was the bishop of Rome and ruler of the Papal States from 16 December 955 to his death in 964. He was related to the counts of Tusculum, a powerful Roman family which had dominated papal politics for over half a century. He became Pope somewhere between the ages of 17 and 25. If he was 17 then he may have been the youngest Pope in history; if not, that title may belong to Benedict IX, who was between the ages of 11 and 20 when elected.

In 960, he clashed with the Lombards to the south. Unable to control Rome easily, he sought help from King Otto I of Germany and crowned him emperor. John XII's pontificate became infamous for the alleged depravity and worldliness with which he conducted his office. He soon fell out with Otto who, in 963, convened a synod in Rome which purported to depose John XII for his crimes and elect Leo VIII as his successor. John XII died several months after the synod declared him to be deposed.

An Italienzug (also known as Romfahrt or Romzug in German, or as expeditio italica in Latin) was the expedition undertaken by an elected king of the Romans to be crowned by the pope as Holy Roman Emperor in the city of Rome. Prior to the reforms of Frederick Barbarossa, the kings of the Romans struggled to muster an army for the expedition, for they needed the formal approval of the Reichstag. If such approval was granted, the king had permission to recruit knights for their military service in Italy for 410 days.

However, the nobility was generally disinterested and inclined to rather substitute a monetary payment for the service. Therefore, the small force tended to be composed of mercenaries and high ranking clergymen, reinforced by loyal Italian cities. Occasionally, the substitution was not enough – Henry V ended up using his wife Matilda's dowry to fund his Italienzug.

Frederick III (German: Friedrich III, 21 September 1415 – 19 August 1493) was Holy Roman Emperor from 1452 until his death in 1493. He was the penultimate emperor to be crowned by the Pope, and the last to be crowned in Rome. He was the fourth King of the Romans and the first Holy Roman Emperor from the House of Habsburg, which was to retain the title with one gap until it was declared at an end by Emperor Francis II, in 1806.

Prior to his imperial coronation, he was duke of the Inner Austrian lands of Styria, Carinthia and Carniola from 1424, and also acted as regent over the Duchy of Austria from 1439. He was elected and crowned King of Germany in 1440. His reign of 53 years is the longest in the history of the Holy Roman Empire or the German monarchy. Upon his death in 1493 he was succeeded by his son Maximilian.