At all events, this was, evidently, the earliest line of approach, by which Mercia, with its contingents, the other Anglian nations and the East Saxons, whom it had either subdued or otherwise allied, invaded Kent; and this continued to be its chief or only access for some years. A single glance, at the geography of the Hoo, will show the value of such an advanced peninsula, as the basis of such an incursion upon the centre of Kent; and as the stronghold from which the subjection of that kingdom could be maintained. We have other means of knowing that it was probably, at least, thirty years before a second or optional approach was secured by way of the east of Kent. This second access must have been a much coveted one, and when it came into hand must have been of great value; particularly in regard to the occasional, or at least frequent, royal residence already established at the Hoo. The Watling Street, the greatest and most frequented of all the highways then existing, led from the very heart of Mercia, in a direct line through Middlesex, to the very isthmus of the peninsula itself. Although Kent had been already invaded, A.D. 676, yet so late as A.D. 695,[72] London remained subject to Essex; but, as we have already seen, only nine years afterwards Twickenham, in the province called “Middelseaxan,” had become subject to Mercia. Some of our most learned historians describe the “Middle Saxons” as a very small people, forming a part of the East Saxons; but they are obliged to confess that they find very little to say about them. It is believed that there never was a separate people called Middle Saxons. They have been created out of a snatched analogy, of the mere name “Middlesex,” with “Essex,” “Sussex,” and “Wessex.” There can be little doubt that Middlesex represents the original civitas, or territory, of the local government, of its urbs or burgh of London, the capital of the kingdom of Essex. Like other great commercial seaports or staples, this already great mart had maintained much of the condition of a free city; and, in passing, along with its territory from Essex to the ascendant power of Mercia, it may not have been by conquest, but by a voluntary exercise of that instinct, to unite in the fortunes of an advancing supremacy, which is often associated with, and perhaps closely allied to, commercial habits. At all events, it is at this time that the name, Middlesex, first comes to light;[73] and it is believed that instead of being, like the names of the Saxon nations, formed by the addition of an adjective; the “middle” of this newer name is a preposition, and that it means, that Anglian acquisition which had now thrust itself _between_ the East Saxons and the South and West Saxons. The Anglo-Saxon Dictionaries produce an example, from one of the glossaries of Ælfric, of “Middel-gesculdru” = the space _between_ the shoulders.