An ancient civilization dating back to the Hittites, Turkey has witnessed all the great empires and conquerors marching on its territory. From Troy, to the Assyrians, from the Persians to Alexander, Rome and the Byzantines, history is encapsulated in this region of Asia Minor. By the end of the 13th century, the Ottomans had begun to expand, eventually encompassing Europe, the Middle East, Arabia, and Iran. After some 500 years, the Ottomans began to weaken. Known as 'the sick man of Europe', the empire saw its possessions begin to disappear. By the first World War, the empire was almost completely reduced and it took the Father of modern Turkey, Kamal Ataturk, to seize power, regain territory (with the help of the Soviet Union) and set the borders of what is modern Turkey. In 1923, it was declared a republic and the last vestiges of Ottoman power (the Caliphate) was officially at an end. Turkey became a founding member of the United Nations following World War II (for much of the war, Turkey maintained a careful neutrality but did end up declaring war on Nazi Germany in 1945). Turkey became a major ally of the United States, which regarded it as an important bulwark both against communism and Islamic fundamentalism. Turkey has faced a variety of political crises over the years, including Cyprus (major conflict with Greece), corruption, and the emergence of Islamic fundamentalist agitation.