 In 1938, for instance, he personally summoned the German ambassador to Sweden and told him that if Hitler attacked Czechoslovakia over its refusal to give up the Sudetenland, it would trigger a world war that Germany would almost certainly lose.Additionally, his long reign gave him great moral authority as a symbol of the nation's unity.Both the King and his grandson Prince Gustav Adolf socialized with Nazi leaders before World War II, though arguably for diplomatic purposes.