The Battle of Mons Graupius was, according to the Roman writer Tacitus, a Roman military victory that occurred in what is now Scotland around the year AD 83 or, less likely, AD 84. The exact place where the battle happened is still debated by historians. Some scholars have questioned certain parts of Tacitus’s description, suggesting that he may have made the Roman success seem greater than it actually was.

Background

Tacitus wrote that Gnaeus Julius Agricola, who was the Roman governor and Tacitus's father-in-law, sent his fleet ahead to frighten the Caledonians. He then led light infantry supported by British auxiliaries to the site, where he found the enemy already present.

Although the Romans had fewer soldiers than the tribes of Britain, they often struggled to make their enemies fight them in open battles. The Caledonii were the last British tribe that remained unconquered and were never completely defeated. After avoiding battle for many years, the Caledonians were forced to fight when the Romans attacked their main granaries, which had been filled with the harvest. The Caledonians had no choice but to fight or risk starving during the winter.

Location

The Battle of Mons Graupius has been a key topic in the study of Roman Scotland. In the 19th century, it was linked to many important Roman sites in Perth and Kinross, from Dalginross to Blairgowrie. With the use of aerial photography and the study of patterns visible from the air in the 20th century, attention shifted to the northeast, where a series of marching camps were found along the route to the Moray coast. This has led some to believe the battle took place in Aberdeenshire, near Bennachie, a clearly defined hill south of a large marching camp at Logie Durno.

Scholars have debated the battle's location for many years. Most of the proposed sites are in Perthshire, north of the River Dee, in the northeast of Scotland. Some authors suggest the battle occurred in the Grampian Mounth, near the North Sea. Roy, Watt, Hogan, and others have proposed that the high ground of the battle might have been Kempstone Hill, Megray Hill, or other hills near the Raedykes Roman Camp.

Sites in Aberdeenshire match descriptions from the Roman writer Tacitus and have uncovered evidence of Roman activity. These elevated areas are also near the Elsick Mounth, an ancient path used by Romans and Caledonians for military movements. Bennachie in Aberdeenshire, the Gask Ridge near Perth, and Sutherland have also been suggested as possible locations.

Historic Environment Scotland has noted the uncertainty about the battle's exact location as the reason it was not included in the Inventory of Historic Battlefields in Scotland.

Battle

According to Tacitus, 8,000 allied support soldiers formed the center, while 3,000 horse riders were on the sides. Roman soldiers were kept in reserve near their camp. Estimates suggest the Roman army had between 17,000 and 30,000 soldiers. Tacitus reported that 11,000 support soldiers and four groups of horse riders were used in the battle, but the number of Roman soldiers in reserve is unknown. The Caledonian army, led by Calgacus (though Tacitus only mentions him giving a speech, which may not be true), was said to have more than 30,000 soldiers. They were mostly positioned on higher ground, with their front lines on flat land and other lines rising in steps up the hill in a curved shape. Caledonian chariots moved across the flat area between the two armies.

After a short exchange of weapons, Agricola ordered support soldiers to attack the enemy directly. These soldiers included four groups of Batavian and two groups of Tungrian sword fighters. The Caledonians were killed or crushed on the lower parts of the hill. Those at the top tried to attack from the side but were outflanked by Roman horse riders. The Caledonians were then defeated and ran into nearby forests, but Roman soldiers chased them closely.

It is said the Roman legions did not fight in the battle, staying in reserve the entire time. Tacitus wrote that 10,000 Caledonians died, while only 360 support soldiers were lost. About 20,000 Caledonians escaped into the woods, where they avoided many of the pursuing Roman soldiers. Roman scouts could not find the remaining Caledonian forces the next day.

In a personal account of the battle by Hector Boece (1465–1536), he was not a historian who lived at the time of the battle. The Caledonians did not leave written records of their own. The battle was described as difficult and closely fought, as written in:

— Hector Boece, Scotorum Historia, IV.54 (1527).

Criticisms of Tacitus's account

Some historians, such as Hector Boece in 1536, have questioned the account of a major victory described by Tacitus, possibly because of a biased view based on national pride. One writer suggested that Emperor Domitian may have learned that Agricola’s claims of a significant victory were false. However, Agricola was still given honors for triumphs and was offered another governorship in a different part of the empire. This suggests Domitian likely believed Agricola had achieved real success. Claims that Agricola made up the entire event and was then avoided by the emperor seem unlikely, as he was honored upon his return.

Aftermath

After the final battle, it was announced that Agricola had successfully conquered all the tribes of Britain. Soon after, he was sent back to Rome, and his position was given to Sallustius Lucullus. It is believed that Rome planned to continue the war, but other military needs in different parts of the empire required soldiers to leave, and the chance to fully control Britain was missed.

Although Agricola’s campaign brought most of modern-day Scotland under Roman control, the Romans did not stay for long. They had little interest in settling the northern areas permanently, as they saw these lands as lacking resources and less important for strategy compared to southern Britain. Within a few years, Roman soldiers withdrew to the area near the Forth–Clyde isthmus, leaving much of Caledonia unoccupied.

In his writings about Roman history from 68 AD to 98 AD, Tacitus wrote: "Perdomita Britannia et statim missa" ("Britain was completely conquered and immediately let go"). This statement shows his disapproval of Domitian’s decision not to unite the entire island under Roman rule after Agricola’s victories.