Frederick III was German Emperor and King of Prussia for 99 days between March and June 1888, during the Year of the Three Emperors. Known informally as "Fritz", he was the only son of Emperor Wilhelm I and was raised in his family's tradition of military service. Following the unification of Germany in 1871 his father, then King of Prussia, became German Emperor. Upon Wilhelm's death at the age of ninety on 9 March 1888, the thrones passed to Frederick, who had been German Crown Prince for seventeen years and Crown Prince of Prussia for twenty-seven years. Frederick was suffering from cancer of the larynx when he died, aged fifty-six, following unsuccessful medical treatments for his condition.

The German Emperor was the official title of the head of state and hereditary ruler of the German Empire. A specifically chosen term, it was introduced with the 1 January 1871 constitution and lasted until the official abdication of Wilhelm II on 9 November 1918. The Holy Roman Emperor is sometimes also called "German Emperor" when the historical context is clear, as derived from the Holy Roman Empire's official name of "Holy Roman Empire of the German Nation" from 1512.