As a result of the November Treaties of 1870, the southern German states of Baden, Hesse-Darmstadt, with their territories south of the Main line, Württemberg and Bavaria, joined the Prussian-dominated "German Confederation" on 1 January 1871.[1] On the same day, the new Constitution of the German Confederation came into force, thereby significantly extending the federal German lands to the newly created German Empire.[2][3][4] The Day of the founding of the German Empire, January 18, became a day of celebration, marking when the Prussian King William I was proclaimed German Emperor in Versailles.