The Holy Roman Empire (sometimes abbreviated H.R.E.) was a loose federation of German and Italian states, originally formed on Christmas of A.D. 800, when Charlemagne, or Charles the Great (742–814), was crowned emperor of the Romans by Pope Leo III (c. 750–816). But after Charlemagne’s death, the empire lapsed and was not fully reinstated until Otto I (912–973) was crowned emperor. Though the empire was strongly associated with the Roman catholic church, disputes between emperors and popes began in the mid-1100s. In 1250 Pope Innocent IV (d. 1254) was successful in gaining independence from the empire for the Italian city-states.

Later in the history of the Holy Roman Empire, the House of Habsburg rose to power. But after the 1648 signing of the Peace of Westphalia, which recognized the sovereignty of all the states of the empire, the title of Holy Roman Emperor was for the most part an honorific one. With the exception of a five-year period (1740–45), the family continued to hold power until 1806, when Emperor Francis II (1768–1835) declared the end of the Holy Roman Empire.