In the summer of 83, Agricola faced the massed armies of the Caledonians, led by Calgacus, at the Battle of Mons Graupius. Tacitus estimates their numbers at more than 30,000. Agricola put his auxiliaries in the front line, keeping the legions in reserve, and relied on close-quarters fighting to make the Caledonians' unpointed slashing swords useless as they were unable to swing them properly or utilise thrusting attacks. Even though the Caledonians were put to rout and therefore lost this battle, two thirds of their army managed to escape and hide in the Highlands or the "trackless wilds" as Tacitus calls them. Battle casualties were estimated by Tacitus to be about 10,000 on the Caledonian side and 360 on the Roman side.