Something that's...

Join me for a moment on the banks of the river Sen.

We're on a dusty sun-based track following the snake-like river as it curves up through northern France.

It's a sweltering day in August 1158 and the heat rising off the dirt road is unbearable.

Just walking around outside on a day like this, you'll sweat through your clothes in a matter of minutes.

On this bit of road, on this particular day, we begin to hear something long before we can see it.

It's a rumble that sounds like thunder, growing louder and louder.

As we round a bend in the track, the source of the cacophony comes into view.

Hundreds of cartwheels grinding, thousands of horses hooves clattering, the clink and clank of nights sweltering in their male armour.

Once the throng gets nearer, we notice stranger sounds in the ding.

The snarl and bark of huge muscular mastiffs the size of small bears, straining on their leashes.

The cry of exotic birds in cages and monkeys jabbering away as they ride on the backs of pack animals.

The chatter of clerks and squires, servants and stewards, and the jangling of countless wagons containing kitchen utensils, beer barrels and treasure chests.

Even mobile chapels. This is the sound of a plantagenous ambassador on the move.

The party has been sent to the French royal court by our old friend, King Henry II, who has now ruled England for nearly four years.

Henry and his queen, Eleanor of Aquitaine, also still control about a third of the land in France.

The diplomats are heading to Paris to offer an alliance to King Louis VII.

The hope is this alliance will bring peace between the two realms and settle a nagging border dispute over a small but strategically vital piece of land known as the Vexa.

But this enormous procession is not led by King Henry or by Queen Eleanor.

In pride of place, ride someone we haven't met yet. Someone who's going to play a pivotal role in the Plantagenet story, someone who will end up even more famous than Henry and Eleanor.

He's a bright, ambitious and vain, 39-year-old Londoner, who's been plucked by King Henry from an obscure career in the church to become the chancellor of England, basically the head of the royal bureaucracy.

He's tall and athletic, with a heavy brow and aqualine nose and slender white fingers.

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