Römischer Kaiser und Römischer König#

Roman Emperor and Roman King: The title of antique rulers (German: Kaiser), derived from the cognomen of Gaius Julius Caesar, was taken over by Charlemagne in the year 800 and by Otto the Great in 962. In the Middle Ages use of the title Kaiser (Emperor) was conditional on the ruler being crowned by the Pope. The election of kings was made independent of papal approval in 1338 and again in 1356; the last Kaiser to be crowned by the Pope was Karl V (1530). In 1508 Maximilian I assumed the title "Elected Roman Kaiser", and from then on the title remained linked to the House of Habsburg (except for the period 1740-45) and continued to be used up to 1806. The German Kingdom derived from the Frankish regnum and was first documented in 919 (as Regnum Teutonicorum). From the 11th century onwards (and continuously after 1125) a German King who was not yet crowned Roman Emperor (Kaiser) was called "Rex Romanorum", on the analogy of the Roman Emperor, and from the 16th century the elected successor to the emperorship was referred to as "Roman King" as long as the Kaiser was still alive.