The Constituent Assembly of Luxembourg was a constituent assembly called in 1848 in Luxembourg to write and pass a new national constitution. The Grand Duchy had been administratively separate from the United Kingdom of the Netherlands since the Belgian Revolution in 1830, but remained in personal union with the Netherlands. The first constitution had been passed in 1841 under William II, but it was a very conservative document, affirming the autocracy of the King-Grand Duke. With the outbreak of the Revolutions of 1848, William changed from a conservative to a liberal, allowing for the preservation of the monarchy in the face of an upsurge in liberal sympathies.