Seán Russell had arrived in Berlin on 5 May 1940, four days after arriving in
Genoa from the United States. Russell was informed of
Operation Mainau, the plan to parachute Dr.
Hermann Görtz into Ireland. Russell was asked to brief Görtz on Ireland before his departure that night, but missed his takeoff from the
Fritzlar airfield near
Kassel. By 20 May, Russell had begun training with
Abwehr in the use of the latest German explosive ordnance. This training was conducted at the
Abwehr training school/lab in
Berlin-Tegel, which specialised in the design of explosives as everyday objects. Russell also visited the training area for the
Brandenburg Regiment, the 'Quenzgut,' where he observed trainees and instructors working with sabotage materials in a field environment. As he had received explosives training, his return to Ireland with a definite sabotage objective was planned by German Intelligence. His total training time with German Intelligence lasted over three months. ==Immediate context==