Bismarck issues an ultimatum to Denmark on…

Bismarck issues an ultimatum to Denmark on January 16, demanding that the November Constitution should be abolished within forty eight hours.

This is politically impossible, particularly given the short deadline, and the demand is consequently rejected by the Danish government.

All the inland waters (Eider River, Treene, Schlei, and the marshes east of Husum and around the Rheider Au), which the Danes are relying on as defense to guard the flanks of the Dannevirke, are frozen hard and can be crossed easily.