 Spain also supported Ferdinand against the Republic of Venice during the Uskok War in 1617–18.The Diets of Bohemia and Hungary confirmed Ferdinand's position as Matthias' successor only after he had promised to respect the Estates' privileges in both realms.The different interpretation of the Letter of Majesty, which summarized the Bohemian Protestants' liberties, gave rise to an uprising, known as the Second Defenestration of Prague on 23 May 1618.