Karl Caspar, Count von Rex (23 April 1825 – 21 October 1905) was a German politician.

[1] A Canon of Meissen and provost of Bautzen, Rex was a Royal Saxon chamberlain and major in the Artillery.

[3] In 1869 he became a member of the Royal Saxon Association for the Research and Preservation of Patriotic Historical Monuments.

Together, they were the parents of:[1] Count von Rex died in Dresden on 21 October 1905.

[1] Through his son Rudolf, he was grandfather to Countess Marie Louise Rex (d. 1966), wife of Sir Odo Russell,[4][5][a] and Countess Ernestine "Edina" von Rex (1905–1995), wife of Sir Henry Strickland-Constable, 10th Baronet.