 Complete the following phrase:  In 1940 he underwent training as on submarine warfare, and during the Greco-Italian War 194041 he served aboard submarines, undertaking patrols to intercept Italian shipping in the Adriatic Sea. On 31 December 1940 he was promoted to lieutet. In March 1941 he received the War Cross for his service as an officer on board the submarine Nirefs. In April 1941, as the German invasion of Greece had almost overrun the country, as much of the Greek fleet as could be saved was sent to the Allied-held Middle East. Although only a subaltern, Engolfopoulos took over command of Nirefs and led his vessel to the Middle East, where he joined the forces of the Greek government-in-exile. For this initiative he received his second War Cross on 14 September 1944. He then served as executive officer on board the destroyer Pindos, with which he participated in the 