Interesting you mention Gruffydd ap Arthur (Geoffry of Monmouth) and the "Brut History of Tyssilio". Here's a little more of the ancient Brit history suggesting that Geoffry of Monmouth was 'onto-something'. Let's look at Julius Caesar and why he failed two times to invade Britain.

In 55 BC Julius Caesar was keen to bring this Britain; this prosperous island into the Roman Empire, and before he invaded - according to many welsh histories - there were several exchanges of letters between himself and a ruler (Caswallon) of south-east Briton, who is referred to by Caesar as Cassivellaunus. This Caswallon did not like the aggressive way in which Caesar demanded a yearly tribute from Britain, and effectively told Caesar where to stick his rather large head.

In his "De Bello Gallico" - obviously intended for a Roman audience so as to enhance his stature - Julius comments that the Britons knew nothing about "war or arms" and so would be easily subdued.

Such was his thinking when he landed at the beaches of the Kent coast. He and his army of around 12,000 men were met with an opposing force containing hundreds of Statue head of Julius Caesar charioteers who were extremely skilled in chariot warfare, as Caesar himself remarks in his "The Conquest of Gaul".

It should be noted here that while Caesar knew of chariots in the context of racing, he had not expected them to be used for warfare, and certainly not with such devastating efficiency. Chariot warfare had all but ceased in Europe, but Britain being an island, and more importantly an island of warriors descended from Brutus, who himself was a great grandson of Aeneas of Troy - where chariot warfare was the norm - would have obviously been kept alive and vibrant, as a very effective form of warfare.

In a series of bloody hand-to-hand fighting, the invaders were forced to flee, and in this encounter Caesar actually lost his own sword while fighting against a brother of Caswallon called Nennius, who actually trapped Caesar's sword within his shield – and admittedly a little of his head too! Nennius unfortunately died a few days later with the terrible head wound, but the Caesar invasion was dead. Caesar's disastorous second & final attempt was in 54 BC.

Caesar however, returned in the following year of 54 BC with a considerably larger army, around 40,000 men and a few thousand cavalry. Now the British under Caswallon – son of Beli Mawr - allowed Caesar to march his troops unopposed across the Thames and northward into the midlands. Caswallon had a trick up his sleeve, and employed a devious tactic of evacuating all their flocks and their people, well in advance of Caesar, leaving no food for his men to eat. Caesar's army were reduced to foraging the land for anything they could find, and even this proved very difficult as Caswallon sent around 4,000 chariots to constantly harass the poor foraging parties of Caesar's army. Caswallon could have sent a far larger force if required, and as modern archaeology suggests, It seems that they're taking a western perspective on this, and not connecting that dots on their own. I'll give it a try here.

The population of Britons at the time could have numbered as many as ten million. Caesar himself remarks that the population of Britain was huge.

Anyhow, the effect of Caswallon's tactic left Julius Caesar and his army stranded, starving, and demoralized. Matter were about to worsen, as he received news his ships where he originally landed were being attacked by a British army, and to put the icing on the proverbial cake, another British army was moving in to intercept his retreat back across the Thames.

This brilliant strategy forced Caesar into a similar position to that of Napoleon, with his retreat from Moscow. A British army ended up "escorting" the rabble army of Julius Caesar back to his ships, and even Julius Caesar himself writes in his "De Bello Gallico" of the scramble to get aboard the ships - each one now carrying three times their usual numbers of soldiers, due to the devastation of their fleets by both the British army and the fierce sea storms.

Laughably but predictably, even this immense and humiliating defeat for Julius Caesar has been explained away by claiming that the surrounding British army - from whom Caesar and his men scrambled aboard their now heavily laden ships - were in fact performing a servile ceremonial escort duty.

Romans were known for exaggerating their accomplishments. Caesar writes of Kent being "by far the most civilized inhabitants", while near enough calling the rest a bunch of uncouth savages. This is in stark contrast with the unbiased descriptions of the contemporary Greek geographer Strabo, who actually traveled to the places he wrote about, and described the Britons as literate and multilingual, whereas Caesar had barely penetrated the Midlands, and so most likely used these slanders as more justification to "civilize" the "barbarians".

The ancient Brits used chariots like the ancient Greeks and Trojans. Coincidence? The Khumry written language is etymologically the same.