Burg Strontjesmos?

On the walls of the Burg Bentheim castle high on top of the German city Bad Bentheim. It looks like one that Matthieu van Wieringen finds hard to determine. His specimen is colored along the rim.

This lichen is pushing the wonderful idea of being unobtrusive so far as to be practically nondescript! Which nameless lichenologist has named this one? It could have been Verrucaria maura but it's light grey instead of black and I found it high inland instead of low on shoreside rocks near the sea. The description of Buellia aethalea (Steenstrontjesmos) almost fits but then the rim (prothallus) would have to be black. The ecology matches though: megaliths, gravestones, walls of churces and fortifications. Just the thing for the Bentheim vista.

After visiting a number of castles, I get the impression that at least some of the inhabitants were rather bourgeous. The Bentheim castle had a library that intentionally evoked the concept of being very old and archetypical German with its gothic design, but in fact the furniture and decorations were built when the industrial revolution was happening full speed, and the nobility was beginning to feel awkwardly superfluous, nostalgically trying to build their homes back into a past that never was. In the same castle, I saw the usual oil paintings of ancestors, but they looked dull and cheap. They turned out to be a gift from our Dutch queen who had these copied from illustrious originals, to help decorate the place to show status and historic chic. Hunting, dining, drinking and making an impression. In another castle I saw two oil paintings depicting Parsifal on his horse, at nightfall, in awe at finding the dark castle of his opponent Klingsor. If they'd had tv, I bet they'd have watched reruns of Ivanhoe with the youthful Roger Moore escaping their dungeons again and again.