The 20th (2nd Württemberg) Uhlans "King William I" (Ulanen-Regiment "König Wilhelm I." (2. Württembergisches) Nr. 20) were a cavalry regiment of the Army of Württemberg. The regiment was formed in 1809 as dragoons, and was reorganized as uhlans in 1871. The regiment took part in Napoleon's Russian campaign, the Austro-Prussian and Franco-Prussian war. In World War I it served as divisional cavalry for the 26th (1st Württemberg) Division. Formally disbanded 1 May 1919 the regiment existed unit September 1920 as Abwicklungsstelle. The 1st Squadron/18th Horse was bearing the regiment's tradition in the new Reichsheer. This particular regiment was also known as the "Queen's Guard" as the Queen was the "Colonel-In-Chief" of the regiment. It was her regiment.