Zirkus Rosarius (also known as the Wanderzirkus Rosarius) was an Erprobungskommando-style special test unit of the Luftwaffe, specifically of the Luftwaffe High Command, tasked with testing captured British and American aircraft, all of which were repainted in German markings. The purpose of testing allied aircraft was to discover any strengths or vulnerabilities in their design or performance. This information was highly useful in enabling German service personnel to develop tactics designed to counter strengths and exploit any vulnerabilities.