Christian IX, 1818–1906, king of Denmark (1863–1906). A member of the cadet line of Sonderburg-Glücksburg, he succeeded Frederick VII, last of the direct line of Oldenburg. The London Conference of 1852 had settled on him the contested succession to the duchies of Schleswig-Holstein, but in 1863 Christian accepted parliament's annexation of Schleswig to the Danish crown. This precipitated war (1864) with Prussia and Austria, in which Christian lost Schleswig, Holstein, and Lauenburg. In 1866 the Danish constitution was revised, granting the upper chamber more power than the lower. During Christian's reign there was continual liberal agitation for a more democratic constitution. He was succeeded by his son Frederick VIII. A younger son became king of Greece as George I.