The nickname of Iron refers to the fact that, due to his involvement in numerous wars and feuds, he often wore armour.
In 1366, he acted with great force against the city of Korbach, to punish it for disobedience.
As his mother's heir, he was a candidate to inherit the Principality of Lüneburg after the death of Duke William II, also in 1369.
A delegation of the Estates of Brunswick-Lüneburg even travelled to Waldeck to meet him.
In 1371, he created an alliance with Landgrave Henry II of Hesse to fight the robber barons of Padberg.