This is Concept Design work for the upcoming Wildfire Games release, "0 A.D." [link]
"Hellenes" is the correct term for the Greeks. This is a Greek fortress of Castle for use in the game. The Roman Fortress borrows heavily from this shape. Both the Romans and Hellenes Fortresses are penciled on paper w/o any shading whatsoever, then scanned into Photoshop where the shadows are added. I think the PSD shadows add a nice touch.