Third Czech and Slovak Republic
From Tardis Wiki, the free Doctor Who reference
When Jo Grant thought Prague was part of Czechoslovakia in the 23rd century, the Third Doctor corrected her by saying it was now part of the Third Czech and Slovak Republic. (PROSE: Spoilsport) Before that, the Czech Republic and Slovakia had still been separate countries as late as the 22nd century. (PROSE: Life from Lifelessness)
