Otto gains some initial victories against the rebels but he is unable to capture the conspirators and end the rebellion.

Archbishop Frederick seeks to mediate a peace between the combatants but Otto rejects his proposal.

Under Otto's direction, Duke Herman of Swabia leads an army against the conspirators into Franconia and Lorraine.

Otto recruits allies from the Duchy of Alsace who on October 2, 939, cross the Rhine River and surprise Eberhard and Gilbert at the Battle of Andernach.

Otto's forces claim an overwhelming victory: Eberhard is killed in battle, and Gilbert drowns in the Rhine while attempting to escape.

Left alone to face his brother, Henry submits to Otto and the rebellion ends.

With Eberhard dead, Otto assumes direct rule over the Duchy of Franconia and dissolves it into smaller counties and bishoprics answered directly to him.

The same year, Otto makes peace with Louis IV, whereby Louis recognizes his suzerainty over Lorraine.

In return, Otto withdraws his army from France and arranges for his sister Gerberga of Saxony (the widow of Gilbert) to marry Louis IV.

As a reward for Duke Herman's loyalty during the rebellion, Otto arranges for his son Liudolf to marry Herman's only daughter, Ida.