Bygone Sovereign is a term used to refer to the rulers of past empires. The term can be broken down into three crossword solutions: SHAH (4 letters), TSAR (4 letters), and Tsarina (7 letters). A SHAH was the title of the ruler of Persia, now known as Iran, from the 18th century until the 1979 revolution. A TSAR was the title of the ruler of Russia from the 16th century until the 1917 revolution. A Tsarina was the title of the female ruler of Russia, usually the wife of the TSAR.