Science fiction and fantasy in the Czech Republic has a long and varied history. From 1918, when Czechoslovakia became independent, until 1939, when Nazi Germany invaded it, Czech literature enjoyed one of its high points. Czech writers developed their works as aesthetic pieces rather than as platforms demanding independence for the Czech people. The best-known and most important of SF writers was Karel Čapek, whose play R.U.R. (Rossum's Universal Robots) (printed 1920, premiered January 1921), introduced and made popular the frequently used international word robot.