Louis II of Italy is crowned for the second time as Holy Roman Emperor at Rome, at the age of 47. His first coronation was 28 years earlier, in 844, during the reign of his father Lothair I.

Louis II, sometimes called the Younger, was the king of Italy and emperor of the Carolingian Empire from 844, co-ruling with his father Lothair I until 855, after which he ruled alone.

The Holy Roman Emperor, originally and officially the Emperor of the Romans during the Middle Ages, and also known as the Roman-German Emperor since the early modern period, was the ruler and head of state of the Holy Roman Empire. The title was held in conjunction with the title of King of Italy from the 8th to the 16th century, and, almost without interruption, with the title of King of Germany throughout the 12th to 18th centuries.

Rome is the capital city and most populated comune (municipality) of Italy. It is also the administrative centre of the Lazio region and of the Metropolitan City of Rome. A special comune named Roma Capitale with 2,746,984 residents in 1,287.36 km² (497.1 sq mi), Rome is the third most populous city in the European Union by population within city limits. The Metropolitan City of Rome Capital, with a population of 4,223,885 residents, is the most populous metropolitan city in Italy. Its metropolitan area is the third-most populous within Italy. Rome is located in the central-western portion of the Italian Peninsula, within Lazio (Latium), along the shores of the Tiber Valley. Vatican City is an independent country inside the city boundaries of Rome, the only existing example of a country within a city. Rome is often referred to as the City of Seven Hills due to its geography, and also as the "Eternal City". Rome is generally considered to be one of the cradles of Western civilization and Western Christian culture, and the centre of the Catholic Church.

Lothair I was a 9th-century emperor of the Carolingian empire and king of Italy (818–855) and Middle Francia (843–855).