Siedlec was formerly part of the German Empire. In the German Empire, the place was called NN.
The place is now called Siedlec and belongs to Poland.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Siedlec | German Empire | Schildberg | before the Versailles Treaty |
| Siedlec | Poland | Ostrów Wielkopolski | after the Versailles Treaty |
| NN | German Empire | Ostrowo | 1939 |
| Siedlec | Poland | Ostrzeszów | 1945 |
| Siedlec | Poland | Kalisz | 1992 |