Battle of Mons Graupius As described by Tacitus , the Battle of Mons Graupius was a Roman military victory in what is now Scotland , taking place in AD 83 or , less probably , 84 . The exact location of the battle remains a matter of debate . Historians have long questioned some details of Tacitus ' account , and in recent years some historians have expressed doubt that the battle even took place , although that remains a minority viewpoint . According to Tacitus , Gnaeus Julius Agricola , who was the Roman governor and Tacitus ' father - in - law , had sent his fleet ahead to panic the Caledonia ns , and , with light infantry reinforced with British auxiliaries , reached the site , which he found occupied by the enemy . Even though the Romans were outnumbered in their campaign against the tribes of Britain , they often had difficulties in getting their foes to face them in open battle . The Caledonians ( Scottish ) were the last to be subdued . After many years of avoiding the fight , the Caledonians were forced to join battle when the Romans marched on the main granaries of the Caledonians , just as they had been filled from the harvest . The Caledonians had no choice but to fight , or starve over the next winter . Battle details . According to Tacitus , allied auxiliary infantry , 8 , 000 in number , were in the centre , while 3 , 000 cavalry were on the flanks , with the Roman legionaries in front of their camp as a reserve . Estimates for the size of the Roman army range from 17 , 000 to 30 , 000 ; although Tacitus says that 11 , 000 auxiliaries were engaged , along with a further four squadrons of cavalry , the number of legionaries in reserve is uncertain . The Caledonian army , which Tacitus claims was led by Calgacus ( Tacitus only mentions him as giving a speech , probably fictitious ) , was said to be over 30 , 000 strong . It was stationed mostly on higher ground ; its front ranks were on the level ground , but the other ranks rose in tiers , up the slope of the hill in a horseshoe formation . The Caledonian chariotry charged about on the level plain between the two armies . After a brief exchange of missiles , Agricola ordered auxiliaries to launch a frontal attack on the enemy . These were based around four cohorts of Batavians and two cohorts of Tungri an swordsmen . The Caledonians were cut down and trampled on the lower slopes of the hill . Those at the top attempted an outflanking movement , but were themselves outflanked by Roman cavalry . The Caledonians were then comprehensively routed and fled for the shelter of nearby woodland , but were relentlessly pursued by well - organised Roman units . It is said that the Roman Legions took no part in the battle , being held in reserve throughout . According to Tacitus , 10 , 000 Caledonian lives were lost at a cost of only 360 auxiliary troops . This is possibly an exaggeration of enemy fatalities though , as Roman accounts of enemy dead were often suspect , especially with such a huge difference in numbers . 20 , 000 Caledonians retreated into the woods , where they fared considerably better against pursuing forces . Roman scouts were unable to locate the remaining Caledonian forces the next morning . Criticisms of Tacitus ' s account . As has already been suggested , in the absence of any archaeological evidence and with the very low estimate of Roman casualties , the decisive victory reported by Tacitus may be an exaggeration or even an invention , either by Tacitus himself , or by Agricola , for political reasons . This view is not held by the majority of historians , however , who believe an engagement of some description did occur , noting it would be dangerous for an aspiring rhetorician and historian such as Tacitus to have completely fabricated such events . Agricola had been a governor for an unusually long period and his recall to Rome was perhaps overdue , therefore little can be read into this . One author has suggested that Domitian may have been informed of the fraudulence of his claims to have won a significant victory . Despite these claims , it should be noted that Agricola was awarded triumphal honours and was offered another governorship in a different part of the empire , so it would seem unlikely Domitian doubted he had achieved substantial successes . Suggestions that he invented the entire episode and was thereafter shunned by the emperor do not seem likely , given that he was awarded honours on his return . Whilst there may be no other accounts of the battle apart from Tacitus ' s account , this is not unusual , given the scanty nature of sources in general for this period of history . It has been stated there are no references in histories pertaining to the legions that supposedly took part and no legends or traditions inherited by Scottish descendants describing such a battle or Calgacus the supposed leader , but there are no complete ' regimental histories ' for legions of the period . and we have no legends or traditions whatsoever from the native inhabitants of Caledonia . Whilst Agricola was Tacitus ' s father - in - law and therefore was undeniably biased towards the subject of his history , he is generally regarded as one of the most reliable historians of the period . It has been alleged that the account of the battle is a complete contradiction to Caledonian warfare experienced by later Roman expeditions , which was almost exclusively guerrilla warfare , including fort raids , ambushes and other hit - and - run tactics . The Romans found these tactics very frustrating to deal with because they had to spread their forces out , which conflicted with Roman military doctrine . The lightly armoured and fast - moving Caledonian skirmishers and horsemen with their knowledge of the terrain could easily outrun and outmanoeuvre marching Roman columns , ambushing isolated elements and then disappearing again before reinforcements could arrive . But Tacitus , in fact , describes the frustrations experienced by the Romans during their campaign , noting the Caledonian preference for ambush tactics and their reluctance to offer a pitched battle . Clearly the Caledonians understood they had little chance of winning such an engagement and sought to avoid one until Agricola had penetrated deep into their territory and reduced them to the necessity of risking such a dangerous gambit . As noted above , Agricola had advanced far enough to threaten their vital interests . Indeed , his strategy was no doubt formulated with the end in mind of forcing just such an engagement as Mons Graupius . If we are to accept Tacitus ' s account , the victory , though impressive , was not comprehensive , and occurring late in the campaigning season gave Agricola little chance to exploit his success . Contrary to his account , archaeological evidence indicates that Domitian did not immediately abandon all efforts to subjugate the remainder of Britain . The construction of a series of forts beyond the Forth , in particular the legionary fortress of Inchtuthil were perhaps intended to act as a springboard for further advance , and at the very least were intended to control the territory over which Agricola had advanced . Despite this within the next few decades the Romans conducted a staged withdrawal towards the eventual frontier demarcated by Hadrian ' s Wall . Although it is probable that Agricola ' s campaign was a severe shock and setback for the British tribes inhabiting the area that would become Scotland , it did not ultimately achieve the aim of incorporating them into the empire , nor was this ever achieved . Aftermath . Following this final battle , it was proclaimed that Agricola had finally subdued all the tribes of Britain , which is not strictly true , as the Caledonians and their allies remained a threat . Indeed , even if the inflated account of Caledonian fatalities were to be accepted , the bulk of their forces were still intact to fight again . Soon after Agricola was recalled to Rome , and his post passed to Sallustius Lucullus . It is likely that Rome intended to continue the conflict but that military requirements elsewhere in the empire necessitated a troop withdrawal and the opportunity was lost . That Agricola ' s successor ( s ) failed to neutralise the threat to Roman security in the north of Britain had important consequences for the remainder of the period of occupation . Tacitus ' statement " Perdomita Britannia et statim missa " ( Britain was completely conquered and immediately let go ) , denotes his bitter disapproval of Domitian ' s failure to unify the whole island under Roman rule after Agricola ' s successful campaign . Some have doubted whether Agricola had defeated the last of British resistance , pointing to the uneasy peace of the next few decades and the construction and occupation of the Glenblocker fort s and Inchtuthil in succeeding years , bases for a garrison of the southern part of modern Scotland . Battle location . Considerable debate and analysis has been conducted regarding the battle location , with the locus of most of these sites spanning Perthshire to north of the River Dee , all in the northeast of Scotland . A number of authors have reckoned the battle to have occurred in the Grampian Mounth within sight of the North Sea . In particular , Roy , Surenne , Watt , Hogan and others have advanced notions that the high ground of the battle may have been Kempstone Hill , Megray Hill or other knolls near the Raedykes Roman Camp . These sites in Kincardineshire fit the historical descriptions of Tacitus and have also yielded archaeological finds related to Roman presence . In addition these points of high ground are proximate to the Elsick Mounth , an ancient trackway used by Romans and Caledonians for military maneuvers . Bennachie in Aberdeenshire , the Gask Ridge not far from Perth and Sutherland have also been suggested .