"That is all; but its history contains the histories of all the others--in
fact, the whole history of early England." Sir Nathaniel, seeing the
expectant look on Adam's face, went on:

"The history of the Castle has no beginning so far as we know. The
furthest records or surmises or inferences simply accept it as existing.
Some of these--guesses, let us call them--seem to show that there was
some sort of structure there when the Romans came, therefore it must have
been a place of importance in Druid times--if indeed that was the
beginning. Naturally the Romans accepted it, as they did everything of
the kind that was, or might be, useful. The change is shown or inferred
in the name Castra. It was the highest protected ground, and so
naturally became the most important of their camps. A study of the map
will show you that it must have been a most important centre. It both
protected the advances already made to the north, and helped to dominate
the sea coast. It sheltered the western marches, beyond which lay savage
Wales--and danger. It provided a means of getting to the Severn, round
which lay the great Roman roads then coming into existence, and made
possible the great waterway to the heart of England--through the Severn
and its tributaries. It brought the east and the west together by the
swiftest and easiest ways known to those times. And, finally, it
provided means of descent on London and all the expanse of country
watered by the Thames.

"With such a centre, already known and organised, we can easily see that
each fresh wave of invasion--the Angles, the Saxons, the Danes, and the
Normans--found it a desirable possession and so ensured its upholding. In
the earlier centuries it was merely a vantage ground. But when the
victorious Romans brought with them the heavy solid fortifications
impregnable to the weapons of the time, its commanding position alone