 He was buried at "Waldfriedhof" Darmstadt.After World War II, Brentano was one of the founders of the Christian Democratic Union in Hesse and became a member of the Landtag of Hesse in 1946, from 1947 as chairman of the parliamentary group.He also attended the proceedings of the "Parlamentarischer Rat" assembly drafting the Basic Law for the Federal Republic of Germany.