Initially, the Lord High Stewart Ulrich von Schwerin, acted as regent.

As Bishop of Cammin Casimir had many disputes with the city of Kolberg, the capital of the prince-bishopric.

When Barnim X died in September 1603, it was Casimir's turn to rule Pomerania-Stettin, but he was seriously ill and did not take up government.

[2] The modern numbering counts only the members of the House of Griffins who have reached adulthood and reigned.

If one also takes into account family members who never reigned, which was common in the older literature, he would be Casimir IX.