On 15 January 1520, the Czech Kingdom of Bohemia began minting coins from silver mined locally in Joachimsthal (Czech Jáchymov) and marked on reverse with the Czech lion.
The coins were called “Joachimsthaler” which became shortened in common usage to thaler or taler.
The German name “Joachimsthal” literally means “Joachim’s valley” or “Joachim’s dale”.
This name found its way into other languages: Czech tolar, Dutch (rijks)daalder or daler, Italian tallero, Polish talar, Persian dare, as well as – via Dutch – into English as dollar.
Source: Wikipedia