[1][2] On 27 June 1889, William married Princess Maria Teresa of Bourbon-Two Sicilies.

[citation needed] Her parents were Prince Louis, Count of Trani and Mathilde Ludovika, Duchess in Bavaria.

Louis was the eldest son of Ferdinand II of the Two Sicilies and his second wife Archduchess Maria Theresa of Austria.

On 22 November 1880, William's father, Prince Leopold, renounced his rights to the succession of the principality of Romania[4] in favour of his sons.

Having become familiar with the situation there, the 22-year-old William renounced all rights to the succession of the kingdom (since 1881) of Romania by a letter in French dated on 20 December 1886.