Battle of Flarchheim

Battle of Flarcheim was fought between Holy Roman Emperor Henry IV and the German anti-king Rudolf of Swabia on January 27, 1080 near Flarchheim.

Prelude
Rudolf appeared to be vulnerable after losing the support of some of the Saxon princes. Henry decided to take advantage of this vulnerability and marched out against him in the winter of 1079-1080. Rudolf sought out Henry and met him at Flachheim between Eisenach and Mühlhausen in Thuringia.

Battle
Rudolf had arrayed his army on a hill behind a stream. Rather than attack Rudolf and possibly get caught with his forces straddling the stream, Henry opted to march around the obstacle.

What happened in the gathering dark and the ensuing snowstorm is not certain. On one hand there are reports of the Saxons being attacked and driven off after duke Vratislaus II of Bohemia cut down the Saxon standard during the snowstorm. On the other hand, Ekkehard of Aura reports that Otto of Nordheim attacked and plundered Henry's camp before forcing the surrender of the Franconians and the Bohemians. Berthold (possibly Berthold of Ratisbon) states that the armies became separated in the dark and that Rudolf was forced to withdraw to a neighboring village by the cold.

The next day Rudolf returned to the field, but Henry had withdrawn to Franconia and disbanded his army. It is not clear if Henry was defeated or simply withdrew in the face of more resistance than he expected.