The term 'OLD GERMAN RULER' can be summarized as the KAISER, a 6-letter word. The KAISER was the title of the German monarchs from 1871 to 1918, when Germany was an empire. The title was derived from the Latin word for emperor, and was used by the Holy Roman Emperors from the Middle Ages until 1806. The KAISER was the highest authority in the German Empire, and was responsible for the government and military.