west made it possible to combine one of the three legions hitherto stationed there with that stationed in Lindum, and to advance the camp itself from Lindum to the chief place of the Brigantes, Eburacum (York). But, so long as the west offered serious resistance, nothing further was done in the north for the extension of the Roman bounds; at the Caledonian forest, says an author of the time of Vespasian, the Roman arms were arrested for thirty years. [Sidenote: Agricola.] It was Agricola who first, after his work was over in the west, energetically set himself to the subjugation also of the north. First of all, he created for himself a fleet, without which the provisioning of the troops in these mountains, which afforded few supplies, would have been impossible. Supported by this fleet he reached, under Titus (80), as far as the estuary of the Tava (Frith of Tay), into the region of Perth and Dundee, and employed the three following campaigns in gaining an exact knowledge of the wide districts between this frith and the previous Roman boundary on the two seas, in breaking everywhere the local resistance, and in constructing intrenchments at the fitting places; with reference to which, in particular, the natural line of defence which is formed by the two friths running deeply into the land, of Clota (Clyde) near Glasgow, and Bodotria (Forth) near Edinburgh, was selected for a basis. This advance called the whole Highlands under arms; but the mighty battle which the united Caledonian tribes offered to the legions between the two friths of Forth and Tay at the Graupian mountains ended with the victory of Agricola. According to his view the subjugation of the island, once begun, had to be also completed, nay, even extended to Ivernia; and in favour of that course there might be urged, with respect to Roman Britain, what the occupation of the island had brought about with respect to Gaul. Moreover, with an energetic carrying out of the occupation of the islands as a whole, the expenditure of men and money for the future would probably be reduced. [Sidenote: Caledonia abandoned.]