The capital of Czechoslovakia was Prague, which is the largest city in the Czech Republic. Oslo, the capital of Norway, was a four-letter word that could have been used to answer the crossword puzzle question. Prague is a city with a rich history, having been founded in the 9th century and serving as the capital of the Kingdom of Bohemia from the late 13th century until 1918. It is now the capital of the Czech Republic and is home to many cultural and historical sites.