

Maybe I am just a little partial, but doesn't that seem a bit farfetched? We must remember that this account was written not only by the victors(if indeed they were the victors)but by the son in law of the general in command. Perhaps the romans were armed with rocket launchers, M16s, tanks, etc...... I doubt that after a loss of 10,000 fighting men the caledonians could have posed a serious threat to the romans again for many years to come.
This was not the case. The Caledonians continued to raid the roman towns and forts, so much so that great walls were built across the width of the land to keep the caledonians out of the Roman occupied lands. While slowed by the walls they were not stopped. They continued to raid and harrass the Romans.
During the early second century the Romans invaded once again with a legion of 6000 men. The legion disappeared without a trace. This was not recorded by the romans with as much gusto as their victory at Mons Grapius. In the year 181 the Caledonians swarmed across the Antonine wall attacked a roman army and slew a general. Several years of unrest followed. In the year 196 Hadrians walls garrison was left depleted by an excursion into Gaul by the governer of Britain. The northern tribes attacked once again. This time the romans reported that it was two tribes that struck, the Caledonians and the Maetae. The Caledonians living north of Antonines wall the Maetae living close to the wall. The romans were forced to pay them off.
In the year 208 the Emperor Severus launched the most serious invasion since Mons Grapius. The year 211 saw the death of Severus and the end to the invasion. In 306 A.D. the Roman Emperor Constantius invaded once again with pretty much the same results of Severus. From then on the Romans referred to the northern tibes of Britain as the Picts.
One interesting note,the name of the leader of the Caledonians in the 1st century was Calgacus. This is the latinized version of the gaelic name Calgaich, which means swordsman. Now my question is why did the leader of the Caledonians have a leader with an Irish name, when the gaels had yet to(according to historical sources)live in Caledonia for another 400 or so years?

First off what about the name pict? It may be the name the tribes of caledonia used to describe themselves. Perhaps its what the britons called their northern neighbors. The britons refered to blue dyed sails of certain ships as pictae, so its not much of a stretch to imagine them using a similiar term to describe people who dyed their bodies with woad. This would go along with the Romans describing the caledonians as painted men, pictii. In the ancient Irish texts the inhabitants of caledonia were called cruithni which roughly translates as people with images on their bodies.
The texts also mention that the cruithni were not only found in caledonia but in Ireland as well. Could they have been the Firbolg found in the mythological cycle?
In the 2nd century AD Alexanderian geographer Ptolemy recorded the names of 17 tribes living north of Hadrians wall. 12 of them lived north of the Firth of Forth. By the fourth century the people of Caledonia were refered to as picts.
Where did the come from? The story in the Irish texts say they migrated from Scythia to northern Ireland. Eremon the high king, told the cruithni that there was no room for them in Ireland and that they should go east into northern Britain as it was largely uninhabited. The cruithni followed Eremons advice and settled in Alba. The Cruithni found themselves to be without women either due to disease or the fact that they brought none with them, so the Irish gave them wives with one stipulation; kingship must always pass down through the mothers side. This gave the Irish a certain claim over the kingship of the cruithni. Is this story true? well who's to say. Another theory is that the picts the indigenous people of the Isles, the builders of New Grange, the dwellers in Skara Brae, the builders of the megaliths, etc.....
No one is sure if the picts were even of Indoeuropean ancestry or not. Pictish art is very distinct and resembles celtic art. Does this imply that the picts were a tribe of celts? Most scholars feel that this is the case. What they can't agree on is what branch of celts they belong to.
There are many other things that celts and pict share besides art. It is known that the picts practiced a druidic religion, when Saint Columba visited Pictland in the 5th century he had a couple of run ins with the druid Broichan. Before the Dal Riada scots landed in caledonia the Picts were living in a clan based society just as the Irish were.
Northumbrian historian Bede in his history of the English,written in the late 7th century. made some important references to picts. Remember Bede was a neighbor to pictland, living in nearby northumbria,writing this history for his king Ceolwolf,was in no place to lie and spread falsehoods about the picts. He said that the picts spoke a language that was there own, not p-celtic or q-celtic, that they came from scythia(most scholars agree that he meant scandinavia), that they followed a materlineal descent to the kingship, the pictish settlers married Irish wives. He also eludes to the fact that there were picts living in the Galloway region. Modern scholars ignore this statement even though it is backed up by rich pictish finds from the galloway region.