 Olav then went on to study jurisprudence and economics for two years at Balliol College, Oxford.During the 1930s, Crown Prince Olav was a naval cadet serving on the minelayer/cadet training ship "Olav Tryggvason".Olav moved up the ranks of the Norwegian armed forces, rising in the army from an initial rank of first lieutenant to captain in 1931 and colonel in 1936.