List of monarchs of Luxembourg in the context of "William I of the Netherlands"

Charlotte (Charlotte Adelgonde Elisabeth Marie Wilhelmine; 23 January 1896 – 9 July 1985) was Grand Duchess of Luxembourg from 14 January 1919 until her abdication on 12 November 1964. Her reign is the longest of any Luxembourgish monarch since 1815 when the country was elevated to a Grand Duchy.

She acceded to the throne on 14 January 1919 following the abdication of her sister, Marie-Adélaïde, due to political pressure over Marie-Adélaïde's role during the German occupation of Luxembourg during World War I. A referendum retained the monarchy with Charlotte as Grand Duchess regnant.

The County of Luxembourg (French: Luxembourg; Luxembourgish: Lëtzebuerg) was a State of the Holy Roman Empire. It arose from medieval Lucilinburhuc ("Little Fortress") Castle in the present-day City of Luxembourg, purchased by Siegfried, Count of the Ardennes in 963. His descendants of the Ardennes–Luxembourg dynasty began to call themselves Counts of Luxembourg from the 11th century onwards. The House of Luxembourg, a cadet branch of the Dukes of Limburg, became one of the most important political forces of the 14th century, contending with the House of Habsburg for supremacy in the Holy Roman Empire.