With the spirit of the French Revolution pervading all areas of thought, attempts were made to unify Dutch spelling and grammar. Matthijs Siegenbeek, professor at Leiden was officially asked in 1801 to draw up a uniform spelling; the priest Petrus Weiland was asked to write a grammar book. A few years later Siegenbeek published his spelling in "Verhandeling over de Nederduitsche spelling ter bevordering van de eenparigheid in dezelve" (Treatise on Lower Dutch spelling to promote uniformity herein) (1804) and a "Woordenboek voor de Nederduitsche spelling" (Dictionary for the Dutch Spelling) (1805). The government of the Batavian Republic officially introduced Siegenbeek's spelling on 18 December 1804.