Dr Adrian Goldsworthy

It's not quite the perfect spot he wanted earlier, but it's good enough.

It's behind this small river, the Issus.

And it's basically another obstacle as they've done it.

Granicus, we'll wait here.

You can come to us.

And you've got to go through the difficult ground to fight us.

I mean, with any of those plausible figures, we can't prove it.

It was probably bigger than Alexander's.

You're always going to count the enemy twice.

But it's a bit like when you see one of these big demonstrations through the center of London or Paris or wherever, and you get figures in the press.

There were 300,000, a million.

How do you know?

The human mind, we can cope in that's a lot.

But the odds are that nobody sat down and counted everybody.

Darius might have some idea, but it's probably going to be rough.

He doesn't need to as long as the various bits that are supplying them have got enough for everybody.

It's an army that includes more of these Greek mercenary hoplites.

It includes Persian troops that have been trained and equipped to fight in more of a close order style like that.

Spear and shield.

Yeah, basically, rather than the archery on which they've relied in the past.