The various [False Dmitriys](https://en.wikipedia.org/wiki/False_Dmitry) who appeared during Russia's [Time of Troubles](https://en.wikipedia.org/wiki/Time_of_Troubles) following the death of Ivan the Terrible are probably the best-known examples.

The real Dmitry, Ivan the Terrible's youngest son, died (we think) in 1691 in his mother's retreat in Uglich.  It is often assumed the [Boris Godunov](https://en.wikipedia.org/wiki/Boris_Godunov), who had ascended the throne when Dmitry's brother Feodor died, had the nine-year-old boy assassinated.

[False Dmitry I](https://en.wikipedia.org/wiki/False_Dmitry_I) may have been an illegitimate son of a Polish king, but he claimed to be Dmitry, having been spirited out of Uglich by his mother, who had anticipated Godunov's move.  Godunov was extremely unpopular. Supported by Poland-Lithuania, "Dmitry" gathered an army, and in 1605 was poised to take Moscow and the throne when Godunov died. However, "Dmitry's reign only lasted a year. 
 He was killed in 1606 when a mob stormed the Kremlin after a rumor spread by his eventual successor [Vasily IV](https://en.wikipedia.org/wiki/Vasili_IV_of_Russia) that "Dmitry" was going to make Russia convert to Roman Catholicism.  

[False Dmitry II](https://en.wikipedia.org/wiki/False_Dmitry_II) appeared in Poland, where False Dmitri I's widow identified him as her dead husband.  He gathered another army and was poised to take Moscow in 1610 when the Polish contingent of his army deserted him for their king [Zygmunt III](https://en.wikipedia.org/wiki/Sigismund_III_Vasa), who had decided to annex what Russian territory he could, and make his son Wladyslaw the Tsar instead.  (But not before he appointed [Mikhail Romanov's father](https://en.wikipedia.org/wiki/Patriarch_Filaret_of_Moscow) the Patriarch of Moscow).  "Dmitry" fled to the Don Cossacks and conquered a lot of Southern Russia before a disgruntled officer got "Dmitry" drunk after a party, led him away and shot him.

(Meanwhile some [boyars](https://en.m.wikipedia.org/wiki/Boyar) indicated they might support Wladyslaw if he converted to Orthodoxy but Zygmunt wasn't having that.  The Polish occupation of Moscow ended in 1612).

But it wasn't over! [Yet another impostor](https://en.wikipedia.org/wiki/False_Dmitry_III) appeared in 1611, received support from the Cossacks again, and (based in Pskov) was proclaimed Tsar in 1612. But this didn't last long: He had to flee and was captured, taken to Moscow and killed. Whether by the Polish garrison or the Russians besieging them is unlcear.

This _may_ be the end of it, or it may not. The linked Wikipedia article contains one of the funniest things I ever read in Wikipedia: _"Some people argue that False Dmitry IV is just False Dmitry III due to bad record keeping"_. This might just be a joke someone edited into Wikipedia, however.

At the end, the 16-year-old son of the Patriarch raised by False Dmitry II was elected Tsar [Michael](https://en.wikipedia.org/wiki/Michael_of_Russia), beginning the Romanov dynasty that (may have, kind of) lasted until 1918.

This happened during a few other Russian succession crises, such as when [Pugachev](https://en.wikipedia.org/wiki/Yemelyan_Pugachev) led an insurrection against Catherine the Great, claiming to be her murdered husband Peter III.   But False Dmitry I was the only one to actually sit on the throne.