The Reichskammergericht — the Imperial Chamber Court — was one of the two highest courts of the Holy Roman Empire and one of the first attempts at a permanent supreme court anywhere in Europe. It moved to Wetzlar in 1693 after Speyer was sacked in the Nine Years' War and stayed until the empire was dissolved in 1806, leaving its records, its judges, and an entire legal subculture in the small Hessian town.
The museum sits in a former judge's residence and explains the court's procedure and place in imperial law in a clear, well-organised series of rooms. It also goes into the Reichshofrat rival in Vienna and the famously slow pace of imperial justice — cases that ran across generations were normal. Combined ticket with the Lottehaus.