Lemass had the two difficult tasks of developing Irish industry behind his new tariff walls, and convincing the conservative Department of Finance to promote state involvement in industry. Against the background of the Great Depression, he and de Valera engaged in the Anglo-Irish Trade War which lasted from 1933 until 1938, causing severe damage and hardship to the Irish economy and the cattle industry. In 1933, Lemass set up the Industrial Credit Corporation to facilitate investment for industrial development; in the climate of the depression investment had dried up. A number of semi-state companies, modelled on the success of the ESB, were also set up. These included the Irish Sugar Company, to develop the sugar-beet industry, Turf Development Board for turf development, and an Irish airline, Aer Lingus. Years later Lemass described Aer Lingus as his "proudest achievement". These helped create management skills within Ireland, as most people of ability preferred to emigrate.