In 55 B.C., the Romans under Caesar sailed to Britain, from which the Romans had been getting slaves and tin.
Under Claudius in 43 A.D., they established some settlements, and remained for four hundred years; but they lingered rather as conquerors than as colonists, and when they departed to defend their empire, they left little for today beyond some well-constructed roads, the remnants of walls, and the ruins of baths, as at Chester on the border of Wales.
The Romans also left a few names in the language. Latin colonia, "colony", survives in Lincoln. Latin vicus, "village", remains in Warwick and Greenwich (Latin v was pronounced like our w).
The Roman "camp", castra, was more widespread, and took different sounds in different parts of the country. It is still used in Lancaster, in Westchester, and in Worcester. The last of these, a Celtic place name plus the Roman "camp", with the added Saxon word for "county", shire, has come into our current vocabulary as the name of a sauce.