As successor of Albrecht II, Frederick was elected German king in 1440. He was son of Ernst the Iron, who derived from the Habsburger and his wife Cimburgis of Masowien. As duke of Austria, Frederick V became king Frederick IV; his name changed into Frederick III, when he was crowned emperor.
In 1452 he himself, married, at the age of 37, Princess Eleonore of Portugal, who was 21years younger than Frederick.
In 1448 he concluded the Viennese concordat with the Pope and the curia that was in force up to 1806 and regulated the relationship between the Habsburger and the papacy.
Frederick was the last Holy –Roman emperor, who was crowned by the pope in Rome(coronation in 1452 by Pope Nikolaus V, after Frederick only Karl V was crowned by the pope in 1530, however in Bologna). In this function he declined the Imperial Reform that was planned at that time and could just avoid his deselection and the selection of an antagonist by the German electors.