It's a blisteringly hot morning on the 7th of September 1191.

Thousands of crusaders are marching steadily south towards the village of Asuf.

On their right is the ocean, where their fleet of supply ships can be seen in the distance.

And to their left is a great forest.

While the greenery and shade should provide welcome relief to the army,

it's actually making them very nervous because the trees are perfect cover for an enemy attack.

An attack they know is coming.

As they walk, men scan the area and hold their weapons close.

After more than two weeks spent marching in the summer sun, they are exhausted,

but their leader won't allow any lapse in formation.

He's the King of England and Crusader in chief Richard the Lionheart,

and his sights are set firmly on the city of Jaffa.

Today, Jaffa is part of Tel Aviv, and in the middle ages, it's the city of Jerusalem's main port.

Richard wants to seize it from its current occupant, his nemesis, the great Sultan Saladin.

Then he plans to turn inland and trek about 45 miles over the Judean hills until he gets to the city of Jerusalem.

For Richard's troops though, all of that feels a long way off right now.

They've marched from Aka, and it's been hellishly tough.

It's so hot that Richard can only get his men walking in the morning,

and only for a few miles each day, or they start dropping from heat exhaustion and dehydration.

Food is short, and from time to time fights break out over meat from the carcasses of horses who die on the road.

Saladin's army has shadowed them every step of the way.

He's sent in several raiding parties, constantly chipping away at the Crusaders' morale and their discipline.

...