Sepno Pierwsze was formerly part of the German Empire. In the German Empire, the place was called Erlpruth.
The place is now called Sepno and belongs to Poland.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Sepno I | German Empire | Kosten | before the Versailles Treaty |
| Sepno II | German Empire | Kosten | before the Versailles Treaty |
| Sepno, Dwór I | Poland | Kościan | after the Versailles Treaty |
| Sepno, Dwór II | Poland | Kościan | after the Versailles Treaty |
| Sepno | German Empire | Kosten (Wartheland) | 1939 |
| Erlpruth | German Empire | Kosten (Wartheland) | 1939 |
| Sepno Pierwsze | Poland | Kościan | 1945 |
| Sepno Drugie | Poland | Kościan | 1945 |
| Sepno | Poland | Leszno | 1992 |