Dr Adrian Goldsworthy

But it's a strongly cavalry force.

Alexander, by Greek standards, has got a lot of horsemen.

By Persian standards, this is nothing.

But traditionally, the Greeks have had much, much better infantry than the Persians.

Now the Persians have hired their own Greeks, so that's the pick of their army on foot, at least as far as our Greek-based sources are telling us, in that there's always, oh yeah, our chaps are the ones you've got to worry about.

Or who are simply professionals.

They're serving for pay.

The other thing, as soon as you learn anything about the Greek city-states, you learn about the instability, the stasis, the revolutions that occur everywhere.

And very frequently, there are always losers in these, whether it's an aristocracy that takes over or their rivals get thrown out, whether it turns into a democracy, whether it becomes a tyranny.

There are always losers who go elsewhere.

And the best thing, the easiest thing for many of them to do is to sell their spear.

And there's been a long tradition of mercenary service that goes back almost into the Greek Dark Ages.

And that period, and there's even the idea that some of the origins of hoplites and phalanx fighting may have come from organized groups of Greek mercenaries who say, oh, this was a good way of doing it and bring it home with them.

Work out this is how you work as a group.

So there's always been that element.

And think back to Xerxes and Darius, you know, the earlier invasions, they come with Greek exiles.

So there's always these people around.

But yes, it's certainly been magnified by Philip as well.

Not just Alexander, but Philip and his campaigns.

There will be more losers out there.