After painstakingly conquering much of the British Isles and then making it over in significant regard, the Romans left, in 407. It was still Roman Britain, but the Romans were no longer in Britain.

The Picts and Scots saw this, and took advantage. Not satisfied with poking their noses across Hadrian's Wall, they mounted a full-scale invasion and drove the Britons far, far back to the south.

In a panic, the Britons appealed to Rome. This appeal had been turned down the first time around, in 410, when the Western Roman Emperor had admonished the Britons to fight their own battles; but the Britons lived in hope and so tried again. This time, they sent word to the military leader of the Western Empire, Flavius Aetius, in 446. This has been called the Groans of the Britons.

The original Groans would have been written in Latin. The version of that appeal that has survived is from Gildas, a 6th Century monk whose work De Excidio Britanniae has provided much in the way of primary source material for this time period in Britain. The words Gildas used to describe the Britons' appeal were "gemitus britannorum."

The Latin word "britannorum" looks to many people to be the equivalent of "Britannia," or Britain, or the Britons. And "gemitus" in Latin does indeed mean groan, but it also means lamentation, which many historians think is the more accurate translation. An English translation goes on to say that the Groans of the Britons also included this description of the state of affairs: "The barbarians drive us to the sea, the sea drives us to the barbarians; between these two means of death, we are either killed or drowned."

The result was the same, as far as Rome was concerned. The Britons were on their own.

When the Romans left for good, they didn't take every last element of Roman culture with them. For that matter, they didn't take every last soldier with them. Some stayed behind.

The Romans had been around for a few centuries by that time, and they had built a lot of forts and temples and roads. They had killed a lot of native peoples by this time as well, but they had also produced a lot of what is called Romano-British culture. This culture didn't die out; instead, it flourished. Much of the population had embraced the Roman way, in small or large part, in the centuries since Caesar and Claudius had invaded.

As well, the troops in Britain were not just from Italy. They came from all over–from the Germanic provinces and from Egypt and Syria and Spain. Many of these soldiers brought their families with them, and others created melded families of their own by marrying into the local population.