Tsar
title given to a male monarch in Russia, Bulgaria and Serbia
Would a duke hypothetically be subservient to a Tsar?
The Tsar was the highest ruler in several eastern countries. A duke was a title given to important european nobles. Dukes ranked below princes, kings, and queens. Tsars were the equivalents of English Kings.
What is the equivalent of a Tsar in English hierarchy/royalty? Do dukes rank below #1?