In 1871, Germany became a united country, with the former King of Prussia becoming the new German Emperor. Thus, the former Prussian royal anthem became the anthem of the new united Germany. The song also uses the melody of the British national anthem, demonstrating the influence “God Save the King” had on other nations in Europe in the 18th and 19th centuries. This anthem remained in place until the monarchy was abolished at the end of World War I.
Like other anthems of the time, “Heil Dir im Siegerkranz” was never declared an official national anthem, but was the most prevalent anthem in Germany at the time. While it was the anthem used most often for the emperor, it was not the most popular with all the people; since it was the former anthem of the Prussian royal family, those areas that were not part of Prussia before unification were not tied to the anthem. Also, the melody was in use at the time in Great Britain, which was fighting against Germany during World War I.
Special thanks to: Artakorn Jarusriwanna for providing me with the sheet music.
See also: United Kingdom.