Bruno of Altena-Isenberg

Bruno's brother Dietrich died on their return journey and Engelbert was not formally aware that they had been dropped off.[3] The occasion was the event three quarters of a year earlier, when their older brother Count Frederik of Isenberg was involved in the death of their uncle Engelbert II of Berg, Archbishop of the Electorate of Cologne, on 27 November 1225 in Gevelsberg. After his rehabilitation, their brother Engelbert of Altena-Isenberg was restored to his former office in 1237.

Bruno succeeded in 1250 after his brother Engelbert died.[4] Both could defend themselves against the accusation of being complicit after 1226, because they had not been at the talks with Count Frederik in Soest the night before the death of their uncle Engelbert of Berg. But his brother Diederick was. Still, it is unlikely that he, too, was aware. As a bishop, he was better able to assess the consequences. In addition, he knew that Archbishop Engelbert was a trained swordsman, who (as a cleric) had held home (as a cleric) with cousin Adolf I von der Mark for forty days in southern France against the Cathars in 1212, killing 400 inhabitants of Béziers who did not want to be converted; they were burned at the stake.

Bruno was also an important advocate for his young cousins, the surviving sons of his brother Frederik, who were raised by their uncle Henry IV, Duke of Limburg at his stronghold Limburg on the Vesdre. He was on 17 July 1242 with his other brothers (Willem, the youngest is not mentioned) as witness to the party in the transfer of the fief of the castle of Limburg to the Lenne[5] to their uncle Henry IV, Duke of Limburg.

Bruno appears frequently in preserved charters of Bishop Engelbert III of Osnabrück.[6] He himself appears in charters after 1250, such as two years before his death, on 20 and 24 August 1256, when he played a prominent role as a mediator in the conflict between the Cologne Archbishop Coenraad of Hochstaden with the Cathedral Chapter against the Bishop of Paderborn, Simon I of Lippe with his Dom chapter on disputed land ownership in Salzkotten.[7] Coins that were minted in Weidenbrück are known from Bruno as the master of the mint.