following pressure from the other states of the german confederation, as well as russia and france, the danish government committed itself on 23 june 1847 to the construction of a railway from lübeck to büchen in the duchy of lauenburg to connect with the berlin–hamburg railway. among the supporters for lübeck's proposal were such renowned figures as alexander von humboldt, klemens von metternich and the king of prussia, frederick william iv.