Henry IV is trying to unite his forces from southern and western Germany with those of Bohemia and Meissen.

To do so Henry has to bypass the Saxon allies of Rudolf.

Henry successfully draws off the Saxons by feigning a move toward Goslar, while his main army crosses Thuringia eastwards along Saxony's southern border.

Henry is hoping to meet up with the other half of his forces on the Saale or Elster Rivers.

Rudolf's army soon realizes its mistake and pursues Henry.

Rudolf catches Henry's army on the western bank of the Elster near Hohenmölsen.

While his Bavarian contingent may have joined him, the contingents from Bohemia and Meissen are still on the far bank.

Henry retreats to a swampy valley called the Grona.

The battle begins with knights from both armies trading insults.

Henry is initially protected from Rudolf's army by the swampy ground.

Nearby is the bridge over the Elster to the town of Zeitz.

The bridge is being held against Henry, probably by the townsmen.

To meet up with his other forces, Henry will either have to force the bridge or build his own crossing.

Meanwhile Rudolf wants to prevent Henry's escape.

The long pursuit has weakened the cavalry.

Rudolf orders the knights with tired horses to dismount and strengthen the infantry.

Otto of Nordheim leads these forces on a direct assault across the swampy Grona as the remains of Rudolf's knights attempt to circle the swamp.

While Henry and Rudolf's knights fight on the periphery of the swamp, Otto is able to force his way through Henry's screening force and breaks into Henry's camp.

Otto retains control of his force and prevents them from plundering the camp.

Otto's force then falls on the remains of Henry's army engaged with the rest of Rudolf's forces.

Henry's army breaks; many of his warriors drown in the Elster.

Henry is able to escape.