The thing about the thaler is, it's the basis for the 1 troy ounce SIZE of silver coin, but the thaler was a bit rogue for a coin. But it was the Spanish's discovery of large silver vein in South America which led to standardization of the "dolare". The Spanish found so much silver, it was devalued, such that an ounce of silver became the standard coin.

Interestingly, the Spanish discovery of so much silver in South America led to a devaluation but also re-commoditization of silver as a standard payment. Thik about the might of the British Pound and the original American silver dollar.