Ruth von Kleist-Retzow (by birth, the Countess of Zedlitz-Trützschler: 4 February 1867 - 2 October 1945) was born into the German nobility and married into a Prussian army family.
She was horrified by the rise of National Socialism, becoming involved both with the Confessing Church and, after 1933, with (illegal) opposition to the Hitler government.
She was a particular supporter of Dietrich Bonhoeffer who became a regular guest, and whose students would frequently find a refuge at von Kleist-Retzow's Pomeranian estate.
At the time of his execution Bonhoeffer was engaged to marry von Kleist-Retzow's grand daughter, with whom he was in love.