Here is what I got not about the artifacts and paintings but Egypt and Nubia relationship: Nubia and Ancient Egypt had periods of both peace and war. It is believed, based on rock art, that Nubian rulers and early Egyptian pharaohs used similar royal symbols. There was often peaceful cultural exchange and cooperation, and marriages between the two did occur.
World War II convinced U.S. leaders that the policies of isolationism and appeasement had been mistakes. To counter the growing Soviet threat, they sought new ways to keep the U.S. safe and protect its interests abroad.