Context: In the 19th century, the Tsarist Government of the Russian Empire claimed that Ukrainian was merely a dialect of Russian and not a language on its own. The differences were few and caused by the conquest of western Ukraine by the Polish-Lithuanian Commonwealth. However, the dialects in Ukraine eventually differed substantially from the dialects in Russia.

Question: During what century did the Russian government claim that Ukrainian was a Russian dialect?
Answer: 19th

Question: What Russian government claimed that Ukrainian was not a distinct language?
Answer: the Tsarist Government

Question: The conquest of western Ukraine by what country altered the language of Ukraine?
Answer: Polish-Lithuanian Commonwealth

Question: When did the Russian Empire claim the Tsarist language was a language on its own?
Answer: Unanswerable

Question: During which century did the Ukraine claim that Tsarist was simply a dialect of Russian?
Answer: Unanswerable

Question: By who was the Polish-Lithuanian Commonwealth conquered? 
Answer: Unanswerable

Question: To which dialects were Ukrainian dialects substantially similar?
Answer: Unanswerable