You have this somewhat wrong.As mentioned, just like the U.S., Germany, too, has always been made up of STATES.If you found a reference showing that Johannes Wedemeier was from Hanover, then that reference is to what was until 1866 the German STATE of HANOVER (in German: Hannover), the capital of which was the city of HANOVER (in German: Hannover).The reference is to the state, not to the city.That was a misunderstanding on your part, having thought the reference was to the city.(Just like New York State in the U.S. has a New York City, the German state of Hanover had a city called Hanover.)
Until 1945 and its dissolution by the Allies following World War II, Germany's largest state by far was PRUSSIA (in German: Preussen, or if written with the German character "scharfes S", Preußen; pronounced: PROY-s'n), the capital of which was the city of BERLIN.(Following German unification in 1871, Berlin became Germany's national capital as well.)Due to its vast size, Prussia was divided into provinces.
As did most of the major German states, Hanover sided with Austria (back then, a German state like any of the others) against Prussia in the Austro-Prussian War, or Seven Weeks War, of 1866.Austria and her allies were defeated.Prussia thereupon annexed Hanover, which then became what was until 1945 to remain the Prussian province of Hanover.
Here is where an additional misunderstanding on your part comes in:
Following World War II and the break-up of the vast state of Prussia by the Allies, the Prussian province of Hanover, the state of Oldenburg, and the two very small states of Brunswick (in German: Braunschweig) and Schaumburg-Lippe combined to form today's new postwar north-central German state of LOWER SAXONY (in German: Niedersachsen), with the city of HANOVER (in German: Hannover) as its capital.
Lower Saxony only came into existence less than 65 short years ago, so Lower Saxony has nothing whatever to do with Johannes Wedemeier.
I will also mention that Lower Saxony has no connection whatsoever to the German state of SAXONY (in German: Sachsen), the capital of which is the city of DRESDEN, and the largest city in which is LEIPZIG.The two states don't even share a border.
Here is the link to a map of pre-1945 Hanover so that you know what it looked like, Hanover shown in the purplish color.To give you an idea of size, Hanover covered an area about the same as that covered by the U.S. states of Maryland and Delaware combined: