One would think that since Russia had nobility, that it would follow normal nobility titles, like in England. One would think wrong. This is Russia remember? The country that Churchill described as "a riddle wrapped up in a mystery inside an enigma". Probably part of the reason why it fascinates me so.
Once you get the hang of it, Russian nobility titles are quite easy to remember and it doesn't get near as confusing as, say, what do you call the second cousin of the Duke of Whatever.
At the very top is the tsar. He was the King and Emperor of All The Russias. Peter the Great is the one who first accepted the title of Emperor. Prior to that, tsar just meant king. His wife was the tsaritsa. Not the tsarina, that's not an actual term in the Russian language, and they would know after all. It's tsaritsa.
The children of the Tsar and Tsaritsa are the Grand Dukes and Grand Duchesses. The most famous example of this is of course the children of Nicholas and Alexandra. The Grand Duchesses were Olga, Tatiana, Maria and Anastasia. It's also easy to remember what order they were born in. OTMA. That was the abbreviation they used to refer to each other as a group. (Anastasia, btw, was not one of the missing skeletons as previously believed and purported by Anna Andersen. And the two missing skeletons were found about a week ago)
Alexei was a Grand Duke and the tsarevich. That means he's the Crown Prince. He was actually tsar for a grand total of one day after his father abdicated. Grand Duke Michael could not be considered the tsar until he accepted the abdication of his brother. Until he did, Alexei was the Tsar.
The title of Grand Duke and Grand Duchess could ONLY be bestowed on the children of the tsar. That part is quite simple. But their children could not be called Grand Duke or Grand Duchess. Usually they were princes and princesses.
Underneath that is Prince and Princess. The kicker is you didn't have to be related to the tsar in any way to be a prince or princess. It was a title that could be handed out like a dukedom or earldom in England. Then comes Count and Countess, or as it's called in Russian a graf. Then comes baron. Then you've got your landed gentry, the skilled tradesmen and then the peasants.
In some ways it's a little odd, but also very easy to keep track of once you get used to its simplicity. And honestly, this is about the only thing that Russia has ever done simply.