If the invaders are stronger than the people whom they attack, they go on thrusting back their foes till these reach some strong position where, by the aid of mountain, river, or marsh, they are able, at any rate for a time, to hold their own. Thus, a border-line is always determined by some natural feature of the country which gives the defenders an advantage. The attackers will not always operate from the same locality, and the defenders will not always fall back in the same direction; the two sides, also, will vary in power from time to time. For these reasons a border-line, especially in the old fighting days, was often altered. When the Romans invaded Britain they gradually conquered the southern part of it, but they could not subdue the wilder north; one of their boundary lines was drawn from the Solway to the Tyne; then they fought their way further north and their next definite boundary was a line running from the Forth to the Clyde. Along each of these boundaries they built a great wall, and to this day parts of these Roman walls remain. But it is worth noting that neither of these wall border-lines stands upon the present border, one being all in England and the other all in Scotland. When the Romans left Britain, called back to defend their own native land from invasion, there followed a brief period for which we have no definite record of events in this island. This is the period of King Arthur, and none can say how much is true in the Arthurian legends. But history begins to become clear again about the time that the Angles came in their ships across the North Sea, bent on conquest. They landed on all the natural harbours of the east coast, driving the Britons back and taking the land for themselves. The fact that they landed on the East and drove the Britons westward, leads us to think that sooner or later a boundary would have been formed dividing the island into the east side (for the Angles) and the west side (for the Britons). Now that is exactly what did happen. The border-lines were nowhere like the present ones. The northern kingdom of the Angles reached to the Forth, where these people founded Edinburgh (Edwin’s burgh). On the west the Britons had sway in Cornwall (Corn-Walles), Wales, Cumbria (which stretched from the Mersey to the Solway), and Strathclyde (from the Solway to the Clyde). North of the Forth was the country of the Picts; while the Scots were a race recently come from Ireland, and they only owned what we now call Argyleshire, and the islands lying near to it. Not one inch of the present Border was at that day in the border-line!