As the Austro-Hungarian Empire disintegrated in the final days of World War One, Slovak political representatives meeting in the town of Turčiansky Svätý Martin issued a declaration endorsing union with the Czech lands to form a single independent state. Combined with the Czech declaration of independence days earlier in Prague, the move cemented the birth of Czechoslovakia, a multiethnic democracy carved from the wreckage of the Habsburg monarchy.
The Martin Declaration emerged from a hastily convened assembly of Slovak politicians, clergy, and intellectuals who gathered even as Austro-Hungarian authority was visibly crumbling around them, with soldiers deserting the front and empire-wide strikes paralyzing supply lines. Delegates faced genuine danger traveling to the meeting, since local authorities loyal to Budapest still technically held power in the region.
The declaration explicitly affirmed that Slovaks constituted, linguistically and culturally, part of a single Czechoslovak nation, a formulation that papered over real differences between the two peoples but provided crucial legitimacy for the new state's borders and its claim to the mountainous Slovak territories long administered from Budapest.
Tomáš Masaryk, lobbying in the United States and Western Europe throughout the war, became the new republic's first president, with Slovak leader Milan Hodža among the many who worked to fuse the two halves into a functioning government. Czechoslovakia survived as an independent democracy for two decades until the Munich Agreement and Nazi occupation dismantled it in 1938 and 1939, though it would twice be reborn before finally splitting peacefully into the Czech Republic and Slovakia in 1993.