208] [Sidenote: A.D.

209] From this time those walls become the principal object in the British history.

The Caledonians, or (as they are called) the Picts, made very frequent and sometimes successful attempts upon this barrier, taking advantage more particularly of every change in government, whilst the soldiery throughout the Empire were more intent upon the choice of a master than the motions of an enemy.

In this dubious state of unquiet peace and unprosecuted war the province continued until Severus came to the purple, who, finding that Britain had grown into one of the most considerable provinces of the Empire, and was at the same time in a dangerous situation, resolved to visit that island in person, and to provide for its security.

He led a vast army into the wilds of Caledonia, and was the first of the Romans who penetrated to the most northern boundary of this island.