Complex sentence: On 1 January 1871, the country received a new constitution that gave it the name "German Empire" but largely remained the same, which is why the North German Confederation continues as the German nation state which still exists today.
Split into simpler sentences: On 1 January 1871, the country received a new constitution that gave it the name "German Empire". The North German Confederation continues as the German nation state which still exists today.