Original Theresa Thalers were issued in the Austrian State of Burgau in 1780. The originals look essentially identical to the restruck coin except for a few minor variations. But, starting in 1781, the exact same coin, even with the exact same date, was struck by Austrian and other mints and these restrikes continues to this day. The coins are used as 'Trade Coinage' in locations where local coins are not available. One catalog estimates that 800 million of these coins have been struck. There are only about one dozen original coins known to exist.You have a nice coin. But it is not very valuable. Here is a picture of a recent restrike. It is a beautiful coin.