Blumenau was formerly part of the German Empire. In the German Empire, the place was called Blumenau.
The place is now called Czechy and belongs to Poland.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Czechy | German Empire | Gnesen | before the Versailles Treaty |
| Czechy | Poland | Gniezno | after the Versailles Treaty |
| Blumenau | German Empire | Gnesen | 1939 |
| Czechy | Poland | Gniezno | 1945 |
| Czechy | Poland | Poznań | 1992 |