Nassau dispute

The Nassau dispute is an ongoing dispute concerning the leadership of the House of Nassau, a noted European royal dynasty, between the members of its two cadet branches, namely the House of Orange-Nassau and the House of Nassau-Weilburg.

The dispute began in 1924 when, in the aftermath of the First World War, King Frederick, the head of the House of Orange-Nassau, one of the two main branches of the House of Nassau, issued a royal proclamation known as the "Luxembourg Proclamation" that effectively disqualified the members of the rival Nassau-Weilburg branch from continuing to hold the leadership of the House of Nassau on the basis of them being citizens of the defeated German Empire. The proclamation, which generally targeted the descendants of the last ruling Duke of Nassau, resulted in the leadership of the dynasty being effectively transferred over from the older Walramian branch, from which those disqualified by the proclamation originated, to the younger Ottonian branch to which Frederick and his subsequent descendants belong. Following this, the title of Duke of Nassau, which was traditionally held by the heads of the Walramian branch, was officially included as a subsidiary title of the Grand Duke of Luxembourg which has been held by the heads of the Ottonian branch who currently reign over Luxembourg as well as over the Netherlands and the United Kingdom. Meanwhile, the proclamation also effectively bars members of the Walramian branch from setting foot inside Luxembourg, thereby resulting in most of them continuing to live in Germany where their titles are no longer recognised under the country's republican constitution.

Ever since the proclamation went into effect, its validity has been challenged and contested by the surviving descendants of the senior Walramian branch who mostly assert their leadership of the House of Nassau by virtue of seniority and by claiming that as an unrecognised head of the House of Nassau, Frederick's decree was effectively voided. In response, members of the Ottonian branch assert their leadership of the House of Nassau by virtue of being rulers of sovereign states in contrast to the members of the Ottonian branch whose domain of the Duchy of Nassau was annexed by the Kingdom of Prussia in 1866, thereby leaving them relatively powerless and without a country to reign. Regardless, the heads of both the Walramian and Ottonian branches have continued to use the title of Duke of Nassau and generally consider the use of the title by the other side to be illegitimate and unlawful.