Wolfgang Lotz was an Israeli spy who took on the role of a German aristocrat and horse-lover. He befriended the most important Egyptian officials, took them into his home and uncovered many of Egypt's most important military secrets. He then transmitted this information to Mossad headquarters in Israel.
He was instrumental in thwarting Egyptian attempts to use German rocket scientists to develop a missile threat against Israel. Lotz lived a double life, but was eventually arrested by the Egyptians and repatriated to Israel in a very secretive prisoner exchange after the Six Day War.