Image not sharp enough to be 100% positive. The style and "fabric" look wrong for a 17th Century coin. I agree w/C-B-D.
Although I'm flattered at the summons, I have no idea what I've done to convince someone I knew anything about Thalers. So here's what I did. I Googled the obverse legend, "CLYPEVS OMNIBVS IN TESPERANTIBVS." That was enough to identify it as a Bayern Thaler of Maximilian I (confirming the reverse, which is why I searched the obverse, so I wouldn't get muddled in different leaders of similar names). A little further looking netted me a nice one to look at for comparison: Still doesn't make me an expert, but having one right here to compare against the OP coin makes me seriously doubt its' authenticity.
When Authenticating Thalers, keep in mind that the genuine coins have major differences. The photo provided gives us a good idea of what the design should look like and the counterfeit matches it closely; however, these coins were not made from one master hub and major discrepancies do not automatically make a coin of this type counterfeit the way a crudely executed Chinese fake Draped Bust dollar "jumps out." That's why characteristics like the texture of the surface is often more useful than what the actual design looks like on these coins.
