Frederick IV, Duke of Swabia

[1] He was the son of King Conrad III of Germany and his second wife Gertrude von Sulzbach and thus the direct heir of the crown, had there been true heredity.

However, on his death bed, Conrad III allegedly advised the only two persons present, his nephew Frederick Barbarossa and the bishop of Bamberg, to nominate Frederick Barbarossa; and handed the Imperial insignia to him.

Barbarossa wasted no time in getting the Bavarian clerics to endorse him, and had the archbishop of Cologne convene a hurried election.

There the electors of the Empire (minus their "primus inter pares", Archbishop Henry of Mainz, an ally of the pope) elected Frederick Barbarossa to be king, instead of his six-year-old cousin Frederick.

Frederick participated in Barbarossa's campaigns in Italy, becoming one of the many casualties of the Imperial army.