Historically, the Czech lands were called Bohemia (even though it also included Moravia and Silesia) but at some point during Austria-Hungarian ownership it started being referred to as Czech. What caused this change in name? And why, after the creation of their own country, did they not become Bohemia again?
Check this answer from /u/elephantofdoom
https://www.reddit.com/r/AskHistorians/comments/637u0e/when_did_bohemian_turn_in_to_czech/