Henry IV, Duke of Limburg

Engelbert being the principal adviser of Frederick II, Holy Roman Emperor, he was confirmed in the county for life, paying a rent to Henry and Ermengard.

After the execution of his brother-in-law Frederik van Isenberg and the death of his sister Sofia a year later, he was concerned about the fate of the orphans.

For the next 20 years he would also support their rights in armed hand against Adolf Earl of Mark, their father's cousin, who took much of their belongings to himself.

All the while he helped his two teenage cousins Diederik and Frederik of Isenberg junior with men and money in their battle to reclaim their lost county.

The men built a wooden fort for the two cousins as a stronghold and later near a castle on the Schlepenberg on the Lenne, a high fortress they called Limburg.