Directly at the back of the Dreifaltigkeitskirche stands the ruin of a former house that was named after the builder Retschelinus. The Speyer people just call it Retscher.
For a long time it was assumed that this was the place where the Protestation at Speyer 1529 took place. Therefore this was originally the place where the Gedaechtniskirche was to be erected. Today this has been disproved, but the memorial church is still called Retscher-Kirche by the locals, even though it is quite a bit away now.