Of the three sons of Count Franz Anton (1786–1873) and his wife Countess Theresia Anna Maria (née von Brühl), the eldest, Friedrich von Thun und Hohenstein (1810–1881), entered the diplomatic service. After holding other posts he was in 1850 appointed president of the restored German Diet at Frankfurt, where he represented the anti-Prussian policy of Prince Felix Schwarzenberg, and often came into conflict with Prince von Bismarck, who was the Prussian envoy. He was afterwards ambassador at Berlin and St. Petersburg. After his retirement in 1863 from the public service in the Bohemian Landtag and the Austrian Reichsrat he supported the federal policy of his brother Leo. In 1879 he was made a hereditary member of the Upper House. In this position he was, on his death 24 September 1881, succeeded by his eldest son Franz (born 1847).
