The style of the Dutch sovereign has changed many times since the establishment of the Kingdom of the Netherlands due to formations and dissolutions of personal unions, as well as due to marriages of female sovereigns and cognatic successions.
The Kingdom of the Netherlands was proclaimed on 16 March 1815, as a state in personal union with the Grand Duchy of Luxembourg under William I, a member of the House of Orange-Nassau who had already inherited a vast number of titles and lands from his ancestors. On 19 April 1839, the Duchy of Limburg joined the union. William I, William II and William III all ruled as kings, grand dukes and dukes.
In 1866, however, the Duchy of Limburg ceased to exist as a separate polity and instead became integrated into the Kingdom of the Netherlands as a province. William III kept the ducal title and passed it on to his successor, Wilhelmina, but she did not succeed him to the throne of Luxembourg, as the country's succession laws provided for strict observance of Salic law. Thus, the reference to the Grand Duchy of Luxembourg disappeared from the style of the Dutch monarch.
The male line of the House of Orange-Nassau ended with the death of William III on 23 November 1890. His only surviving child and successor, Wilhelmina, married Duke Henry of Mecklenburg-Schwerin on 7 February 1901 and, as customary, assumed the feminine form of her husband's title. The title of Duchess of Mecklenburg was thus added to her full style. The government did not want the House of Orange-Nassau to become extinct on Wilhelmina's death, and so in 1908 she issued a royal decree conferring the title of Prince or Princess of Orange-Nassau to her descendants. Her only child, Juliana, was therefore born not only Duchess of Mecklenburg but also Princess of Orange-Nassau, like previous members of the Dutch royal family.