The grandfather on the mother's side of Ludwig Lenel was the Prussian democrat Friedrich Kapp (1824–1884), who emigrated to the USA, but returned later and became a national-liberal deputy to the German Reichstag and a friend of Bismarck.
Friedrich Nietzsche | Friedrich Schiller | Friedrich Engels | Carl Friedrich Gauss | Karl Friedrich Schinkel | Friedrich Dürrenmatt | Friedrich Hayek | Caspar David Friedrich | Georg Wilhelm Friedrich Hegel | Friedrich Hölderlin | Friedrich Gustav Jakob Henle | Friedrich Ebert | Friedrich Wilhelm Joseph Schelling | Karl Wilhelm Friedrich Schlegel | Friedrich Gulda | Friedrich Rückert | Friedrich Paulus | Johann Friedrich Böttger | Friedrich von Huene | Friedrich List | Friedrich | Christian Heinrich Friedrich Peters | Johann Friedrich Blumenbach | Friedrich Wilhelm Freiherr von Bülow | Friedrich Specht | Friedrich Schleiermacher | Friedrich Schlegel | Friedrich Karl Dörner | Friedrich Fröbel | Friedrich de la Motte Fouqué |