Mons Meg was built in 1449 on the orders of Philip the Good, Duke of Burgundy, and sent by him as a gift to James II, King of Scots, in 1454.

[6] Mons Meg has a diameter of 19 inches (480 mm), one of the largest ever built,[2] weighs 15,366 pounds (6,970 kg)[7] and is 13 feet (4.0 m) in length.

According to this tale, which was lent credence by Sir Walter Scott, when King James arrived at Threave to besiege the Earl of Douglas, the Clan MacLellan presented him with this bombard.

The cannon was drawn down the Royal Mile to the sound of minstrels playing, placed on a new carriage or "cradle" and taken to assault Norham Castle in August 1497.

It was next taken, with other disused ordnance, to the Tower of London in 1754, as a result of the disarming acts against Jacobites aimed at removing weapons or spare cannon from the reach of rebellious folk.

[6] It was returned to the castle in 1829 by order of George IV after a series of campaigns by Sir Walter Scott and the Society of Antiquaries of Scotland.

During the Edinburgh's annual Hogmanay celebrations Mons Meg is fired at the start of the firework display, although the effect is largely theatrical and the gun is not discharged.

After the Union, there was much popular apprehension that the Regalia of Scotland, and the subordinate Palladium, Mons Meg, would be carried to England to complete the odious surrender of national independence.

The Regalia, by his Majesty's special command, have been brought forth from their place of concealment in 1818, and exposed to the view of the people, by whom they must be looked upon with deep associations; and, in this very winter of 1828–9, Mons Meg has been restored to the country, where that, which in every other place or situation was a mere mass of rusty iron, becomes once more a curious monument of antiquity.The gun is not called "Mons Meg" in any contemporary references until 1678.

[15][19] "Meg" may either be a reference to Margaret of Denmark, queen of James III of Scotland, or simply an alliteration, while Mons was one of the locations where the cannon was tested.

Three cannons were founded, one resides in Edinburgh, one in the Flemish town of Ghent at the Friday Market and one in France but this disappeared ages ago.