The Gertrude or Gertrud was the code name of the joint invasion plan for Turkey by Nazi Germany and Kingdom of Bulgaria, the idea began forming in the beginning of the summer of 1942. This code name was eventually changed. The project was abandoned because of the rapid advance of the Red Army in the Caucasus region, and the Allied invasion of Sicily. References Turkey in World War II Cancelled military operations involving Germany Cancelled invasions Cancelled military operations of World War II Germany–Turkey relations Bulgaria–Germany relations Bulgaria–Turkey relations