Its easy, i held a PPL-C (glider pilot license), then a US PPL and the next license i earned was the ATPL. The US PPL was already part of my abinitio training with lufthansa flight training. Germany issued CPLs back then, they were severly restricted though, the largest passenger type that could be flown with them was the DO 228 i believe. Abinitio courses were a direct route to the ATPL (A2) which was upgraded to an ATPL (A1) after 2200 hours without any further test or requirement. Only the A1 allowed one to work as a captain. With JAR FCL i received a normal ATPL of course. Only JAR FCL introduced the "frozen" ATPL, it was a new concept.