The first documentation of Frankfurt being a city has been noted as 794, under the reference of Franconovurt, under the unification of Charlemagne. In 1152, Frederick Barbarossa was elected King of Germany in Frankfurt. The population and size of the city continued to grow steadily as the general population of Europe also grew. As time went on, Catholicism was banned for 15 years, but eventually it was allowed to practice, although it was looked down upon and to do so meant ostracization from the rest of the community. From time to time plague would break out in the city and thousands would die. This kept the population in check and killed many influential leaders of the community. On August 28, 1749, Johann Wolfgang von Goethe was born in the city of Frankfurt. He is among many other notable individuals born in the city throughout its history. By 1800, Frankfurt had 35,000 citizens within the city limits. Frankfurts status as a free city came to an end in 1866, when Prussia unifies with the rest of Germany. During World War II, Frankfurt was essentially destroyed by allied bombing raids, and after the war the city had to be completely rebuilt from scratch. Recently in 1998, Frankfurt was chosen as the city for the headquarters of the European Central Bank.