To fortify the town further, Altena Castle ("Burg Altena") was built, being completed in the first half of the 14th century. Then, in 1560, the castle became the widow's seat of the House of the Counts at Bentheim. As of the 17th century, the castle was gradually sinking into oblivion, slowly falling into ruins that, over the townsfolk's loud protests, were eventually torn down in 1975 to make way for a thoroughfare. Parts of the town's old wall are preserved in the southwest Old Town ("Altstadt").