In 1863, conflict broke out again when Frederick VII died without legitimate issue. According to the order of succession of Denmark and Schleswig, the crowns of both Denmark and Schleswig would pass to Duke Christian of Glücksburg, who became Christian IX. The transmission of the duchy of Holstein to the head of the (German-oriented) branch of the Danish royal family, the House of Augustenborg, was more controversial. The separation of the two duchies was challenged by the Augustenborg heir, who claimed, as in 1848, to be rightful heir of both Schleswig and Holstein. The promulgation of a common constitution for Denmark and Schleswig in November 1863 prompted Otto von Bismarck to intervene and Prussia and Austria declared war on Denmark. This was the Second War of Schleswig, which ended in Danish defeat. British attempts to mediate in the London Conference of 1864 failed, and Denmark lost Schleswig (Northern and Southern Schleswig), Holstein, and Lauenburg to Prussia and Austria.