CHRISTIAN IX. (1818-1906), king of Denmark, was a younger son of William, duke of Schleswig-Holstein-Sonderburg Gliicksburg (d. 1831), a direct descendant of the Danish king Christian III. by his wife Louise, a daughter of Charles, prince of Hesse-Cassel (d. 1836), and grand-daughter of King Frederick V. Born at Gottorp on April 8, 1818, Christian entered the army, and served with the Danish troops in Schleswig during the insur rection of 1848. In 1842 he married Louise daugh ter of William, prince of Hesse-Cassel (d. 1867), and cousin of King Frederick VII. The reigning king, Frederick VII., being childless, the representatives of the great powers met in London and settled the crown on Prince Christian (May 1852), an ar rangement confirmed in Denmark in 1853. The "protocol king," as Christian was sometimes called, ascended the throne on Frede rick's death in Nov. 1863. By putting into force (Nov. 18) the recently drafted constitution under which Schleswig was to be in corporated with Denmark, he came into conflict with the Ger man confederation. (See SCHLESWIG-HOLSTEIN QUESTION.) The German-Danish War followed, which ended by the separation (Oct. 13, 1864) of the duchies from Denmark. Within the nar rowed limits of his kingdom Christian's difficulties were more protracted and hardly less serious. During almost the whole of his reign the Danes were engaged in a political struggle between the "Right" and the "Left," the former being supported in gen eral by the Landsting, and the latter by the Folketing. The king was for many years successful in preventing the Radicals from coming into office, but in he was forced to assent to the formation of a "cabinet of the Left" (see DENMARK: History). In his later years he occupied a patriarchal position among the sovereigns of Europe to many of whom he was related. His eldest son Frederick had married a daughter of Charles XV. of Sweden; his second son George had been king of the Hellenes since 1863; and his youngest son Waldemar (b. 1858) was married to Marie d'Orleans, daughter of Robert, duc de Chartres. Of his three daughters, Alexandra married Edward VII. of Great Britain; Dagmar (Marie Feodorovna), the tsar Alexander III. ; and Thyra, Ernest Augustus, duke of Cumberland. One of his grandsons, Charles, who married Princess Maud of England, became king of Norway as Haakon VII. in 1905, and another, Constantine, crown prince (afterwards king) of Greece, married a sister of the German emperor William II. Christian was also the ruler of Iceland. He died at Copenhagen on Jan. 29, 1906, and was buried at Roskilde.