During the Battle of Fohse, Magdeburg managed to capture Otto and lock him in a cage.

Otto's councillor Johann von Buch paid a ransom of 4000 pounds silver to have him released.

[1] Eric was finally appointed Bishop of Magdeburg in 1283, after Pope Martin IV had given his blessing.

In 1278 he joined King Ottokar II of Bohemia on a campaign in Hungary, where they clashed with Rudolph I of Germany.

The Peace of Rostock of a 1283 created an alliance led by the City of Lübeck, uniting the cities of Wismar, Rostock, Stralsund, Greifswald, Szczecin, Demmin, Anklam, Duke Bogislaw IV of Pomerania, Prince Wizlaw II of Rügen, and Duke John I of Saxony against Brandenburg.

In the Treaty of Vierraden of 1284, Otto IV and his co-rulers returned the Pomerelian territories they had conquered earlier.

In this, Otto was in league with the Bohemian king (his former ward and prisoner Venceslas) who actually was instigator of anti-Habsburg stance and the candidacy of Adolf.

In 1292, Otto IV purchased the Margraviate of Landsberg and in 1292 the County Palatine of Saxony, a territory in the Saale-Unstrut area.

In 1298, Otto IV participated in the overthrow of King Adolph, but not in the military campaign against him.

Otto IV was also involved in feuds against Lord Nicholas I of Rostock, Prince Wizlaw II of Rügen, Dukes Henry I of Brunswick-Grubenhagen and Albert II of Brunswick-Wolfenbüttel and Göttingen and the Bishops of Brandenburg and Havelberg.

He remarried in 1308, to Jutta, who was a daughter of Count Berthold VIII of Henneberg and the widow of Dietrich IV of Lusatia.

Karl Begas designed statue group 7 of the Siegesallee in Berlin, centered on a statue of Otto IV, flanked by busts of Johann von Kröche (nicknamed Droiseke) and Johann von Buch.