Which was a silver coin used throughout Europe for almost four hundred years?

The thaler was a silver coin used throughout Europe for almost four hundred years. Its name lives on in the many currencies called dollar and the Samoan tālā, and, until 2007, also in the Slovenian tolar.

The roots and development of the thaler-sized silver coin date back to the mid-15th century. As the 15th century drew to a close the state of much of Europe's coinage was quite poor because of repeated debasement induced by the costs of continual warfare, and by the incessant centuries-long loss of silver and gold in indirect one-sided trades importing spices, porcelain, silk and other fine cloths and exotic goods from India, Indonesia and the Far East. This continual debasement had reached a point that silver content in Groschen-type coins had dropped, in some cases, to less than five percent, making the coins of much less individual value than they had in the beginning.