Dear Pete, I think it's time for me to explain you some of the (few) evidences that characterize one of the most ancient military settlement of Italy (and the whole Europe): the Copper Age settlement of Conelle di Arcevia.
Imagine a plain at the top of a very low hill (around 15 meters high), surrounded by other higher hills on the South, West and Northern sides, and by other higher ones, but even more distant of the first ones, on the East side.
To tell the truth, Conelle di Arcevia was located in a valley, but the hills around are all well away from the settlement, out of archer's range, for example.
There're two small rivers in this valley, that connect at a certain point.
The plain of Conelle di Arcevia begin from the junction of these two rivers, and proceeds South for about half a kilometer.
After this distance, the ground lower slowly until it reach the river's level.
So you look from above, and what do you see? a wedge of ground between two rivers.
What did these Copper Age people do? They dug a V-shaped moat on the South side of their settlement, actually making a barrier that transformed the wedge into a triangle.
The moat is 120 meters long, 8 meters deep and 7 meters wide. It's made of two semicircles, with their convex part facing the outer side of the plain. This made archaeologists believe that such a design was thought to allow archers and slingers a crossed fire against incoming forces. The moat has just an entrance, which was in the middle of the two semicircles.
It's also plausible that, while digging the moat, Copper Age people had piled the extra soil on the inside part of the moat, so that they could reinforce it with an artificial scarp, which could also have been further fortified with a stockade.
This was perhaps the defense adopted for the South side of Conelle.
And what about the East and West sides of the triangle?
They were naturally delimited by the two small rivers, plus the hill's slopes, while not that high, are steep nonetheless. Blackberry bushes and brambles grows naturally along the rivers, forming an additional defense. Curiously, the ground along the triangle's borders does not show signs of any artificial intervention, such a scarp.
Perhaps the sides were fairly well protected by nature, or perhaps they added stockades to them.
I don't know if this description could help you, but I bet it won't disturb
Next time I'll describe you our Iron Age hillforts
Greetings,
Mauro.