The ruler of Rus­sia is called the tsar or emper­or (the titles are inter­change­able); his wife is either the tsar­it­sa or empress; and his male heir is called the tsare­vich. His oth­er chil­dren are giv­en the titles of grand duke if male, or grand duchess if female.These last titles are passed down just one more gen­er­a­tion, so a tsar’s grand­chil­dren are also grand dukes and grand duchess­es. But a tsar’s great grand­chil­dren hold only the rank of prince or princess. Thus grand dukes and grand duchess­es out­rank princes and princesses.

From Before You Begin in The Fam­i­ly Romanov: Mur­der, Rebel­lion, and the Fall of Impe­r­i­al Russia.

Pho­to: The fam­i­ly of Tsar Nicholas II of Rus­sia. Left to right: Grand Duchess Olga, Grand Duchess Maria, Nicholas II, Alexan­dra, Grand Duchess Anas­ta­sia, Tsare­vich Alex­ei, Grand Duchess Tatiana.

Pho­to Attri­bu­tion: By Bois­san­nas et Eggler, St. Peters­burg, Nevsky 24. [Pub­lic domain], via Wiki­me­dia Commons