Frederick, a son of Reginar, Duke of Lorraine, immediately upon succeeding to the Archbishopric of Mainz in 937, had acted as an opponent of Otto I, one of the most consistent opponents he will face.

In 939, he had joined the rebellion of Eberhard III of Franconia, Gilbert of Lorraine, and Henry I of Bavaria.

He had been imprisoned in Hammelburg for a while.

He had plotted with Henry to assassinate Otto in Easter 941 in Quedlinburg, but they had been discovered and put in captivity in Ingelheim, being released and pardoned only after doing penance at Christmas of that year.

Frederick had refused to accompany Otto to Italy in 951.

He participates in 953 in another rebellion with King Otto’s son Liudolf, Duke of Swabia, and his brother-in-law Conrad, Duke of Lorraine.

Conrad is the son of Werner V, Count of the Nahegau, Speyergau, and Wormsgau.

His mother Cunigunde is a daughter of Conrad I of Germany.

In 941, he had succeeded his father in his counties and obtained an additional territory, the Niddagau.

In 944 or 945, he had also been invested with Lorraine by King Otto I.

In 947, he had married Liutgarde, daughter of Otto and Edith, daughter of Edward the Elder, King of England.

He and Liutgard have one son, Otto of Worms, later duke of Swabia and Carinthia.

King Otto, who bitterly complains about Conrad's ingratitude, is lured to Mainz.

The rebels, abandoned by the Lorrainers and without Henry's support this time, are easily crushed and punished.

Conrad is deprived of Lorraine, which is instead granted to Otto's brother, Bruno I, Archbishop of Cologne.

Eventually Conrad and Otto are reconciled.

Frederick tries to distance himself from the fighting, but will die before anything can come to him.