Historically, Burg Altenfils was first mentioned around 1180 in the list of possessions of Count Siegfried von Bonenburg, who died in 1144. It then passed by inheritance to the Duke of Saxony, Henry the Lion, and is mentioned again in 1200 in the partition agreements of his sons. It was not until the end of the century, specifically in 1294, that Altenfels was mentioned once more. The Archbishop of Cologne promised the citizens of Brilon, who had helped rebuild his castle, that no harm would come to them from it in the event of war. In 1307, 1325, and 1326, castle men are still mentioned at the castle, so it can be assumed that it still existed at that time.








