The springs appear in writing for the first time in 1247, six years after the Mongol invasion, when Béla IV was reorganising his whole kingdom and putting land into the hands of men who would build castles on it. From the thirteenth century to the nineteenth, the land here with its thermal water belonged to whoever held Trenčín Castle. That single fact explains six hundred years of the spa's history: this was never an independent town with a charter of its own, it was an asset on a castle's estate, and it prospered or was neglected according to what its lord wanted from it.Pramene sa v písomnostiach prvý raz spomínajú roku 1247, šesť rokov po vpáde Mongolov, keď Belo IV. prestavoval celé kráľovstvo a rozdával pôdu tým, čo na nej postavia hrady. Od 13. do 19. storočia patrilo územie s termálnou vodou vždy tomu, kto držal Trenčiansky hrad. Táto jediná skutočnosť vysvetľuje šesťsto rokov dejín kúpeľov: nikdy to nebolo samostatné mesto s vlastnou listinou, bol to majetok hradného panstva a prosperoval alebo chátral podľa toho, čo od neho jeho pán chcel.
