Henry XXI, Count of Schwarzburg-Blankenburg German count (1418–1488) Parents Henry XIX, Count of Schwarzburg-Blankenburg Catherine von Braunschweig Children Günther XX, Count of Schwarzburg-Arnstadt Hendrik XXVII van Schwarzburg Günther XXI, Count of Schwarzburg-Sondershausen Günther XXII, Count of Schwarzburg-Blankenburg Siblings Anne von Schwarzburg-Sondershausen Partners Elisabeth of Cleves, Countess of Schwarzburg-Blankenburg