Before his departure, the prudent general had provided for security as well as for dominion.

He had observed, that the island is almost divided into two unequal parts by the opposite gulfs, or, as they are now called, the Friths of Scotland.

Across the narrow interval of about forty miles, he had drawn a line of military stations, which was afterwards fortified, in the reign of Antoninus Pius, by a turf rampart, erected on foundations of stone.

This wall of Antoninus, at a small distance beyond the modern cities of Edinburgh and Glasgow, was fixed as the limit of the Roman province.

The native Caledonians preserved, in the northern extremity of the island, their wild independence, for which they were not less indebted to their poverty than to their valor.