Kozje was formerly part of the German Empire. In the German Empire, the place was called Drachenburg.
The place is now called Kozje and belongs to Slovenia.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Drachenburg | Austro-Hungary | Rann/Brežice | before the Treaty of Saint-Germain |
| Kozje | Austro-Hungary | Rann/Brežice | before the Treaty of Saint-Germain |
| Kozje | Yugoslavia | Šmarje | after the Treaty of Saint-Germain |
| Drachenburg | German Empire | Rann | 1941 |
| Kozje | Yugoslavia | Celje | 1945 |
| Kozje | Yugoslavia | Socialistična rep. Slovenija | 1992 |
| Kozje | Slovenia | Slowenien | 1991 |