The term 'OLD TURKISH LEADER' can be solved by the crossword solution 'SULTAN' (6 letters). A Sultan is a title given to a ruler of an Islamic country, usually in the Middle East or North Africa. Historically, Sultans were the rulers of the Ottoman Empire, which was a powerful empire that lasted from 1299 to 1922. The Ottoman Empire was centered in what is now Turkey, and so the term 'OLD TURKISH LEADER' could refer to any of the Sultans who ruled the Ottoman Empire.