Klasak was formerly part of the German Empire. In the German Empire, the place was called NN.
The place is now called Klasak and belongs to Poland.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Klassok | German Empire | Kempen i. Posen | before the Versailles Treaty |
| Klasak | Poland | Kępno | after the Versailles Treaty |
| NN | German Empire | Kempen (Wartheland) | 1939 |
| Klasak | Poland | Kępno | 1945 |
| Klasak | Poland | Kalisz | 1992 |