Rule Number Fifteen of the Rules of Genealogy: Germany in 1864 is not a place.
Well, obvious, you might say, but do U.S. Census records lie? I guess so because if you go to the 1870 U.S. Federal Census, you can see a lot of people from a place that doesn't exist. Just for the record. Here is a quote to help with the issue.
Until 1871, Germany had been divided into dozens of small states. This was the old Holy Roman Empire of the German nation, which had existed for 900 years when it finally collapsed under Napoleonic pressure. This was also known as the old Reich, or the First Reich (Reich is the German term for empire). See: https://www.wondriumdaily.com/the-creation-of-a-nation-state-bismarcks-unification-of-germany/#:~:text=Until%201871%2C%20Germany%20had%20been,the%20German%20term%20for%20empire).
This Rule is about accurately recording the place that events occurred as it was known at the time.