Its copying the rare early tetradrachms of this style from Athens. But it differs in the brow of the helmet and in the eyes on the obverse. I illustrated some of the technical issues on the reverse. I'm going to have to say fake, sorry. Don't give up yet, Toad!
Since no one has given a definitive answer I will bring the bad news. I have see quite a few Athenian Tetradrachms. Your Example is fake. The designs are not correct, and there are casting marks. A good way to tell an authentic coin is if it has a punch mark or wedge taken out of it. Nearly 95% of authentic examples do. This is what an authentic version looks like. http://cgi.ebay.com/Athens-Attica-A...5|66:2|65:12|39:1|240:1318|301:1|293:1|294:50
ens, What is the purpose of the test cut on a genuine coin? Is it to show the coin is not plated? And I'm sure the test cut was made in ancient times to ensure the coin was genuine when it was used in commerce.
While the designs may not be consistent with the bulk of Athenian coinage, they do resemble the earliest archaic tetradrachms, as I already mentioned. Here is the best example I could find on short notice: The cuts you speak of are far from the best method of counterfeit detection, as these are themselves often counterfeited! http://www.forumancientcoins.com/fakes/displayimage.php?album=search&cat=0&pos=14
If you look close on the obverse pic, you'll see the nose looks funny, sorta like it has a piece of armour covering it. I don't know what that kind of helmet is called but that is another problem I have with this piece, since other pieces don't seem to have that type of helmet on. Plus, the chin seems too pointy. Ribbit