The twins Dietrich and Sabine were born on February 4, 1906, the sixth and seventh of eight children. Their parents, Karl Bonhoeffer, professor of psychiatry and neurology, and his wife Paula, nee von Hase, lived in Breslau at the time. The family roots, however, were not in Silesia, but in Swabia, Thuringia, and Prussia.
…Through this grandmother (Clara von Hase, nee Countess Kalckreuth), Bonhoeffer developed an early sense for music and the fine arts.
~ Eberhard Bethge, Dietrich Bonhoeffer: A Biography (Revised Edition); Chapter 1: Childhood and Youth: 1906-1923, 3.