Inverness was one of the chief strongholds of the Picts, and in AD 565 was visited by St Columba with the intention of converting the Pictish king Brude, who is supposed to have resided in the vitrified fort on Craig Phadrig, on the western edge of the city. A 93 oz (2.6 kg) silver chain dating to 500-800 was found just to the south at Torvean. A church or a monk's cell is thought to have been established by early Celtic monks on St Michael's Mount, a mound close to the river, now the site of the Old High Church and graveyard. The castle is said to have been built by MŠel Coluim III (Malcolm III) of Scotland, after he had razed to the ground the castle in which Mac Bethad mac FindlŠich (Macbeth) had, according to much later tradition, murdered MŠel Coluim's father Donnchad (Duncan I), and which stood on a hill around 1 km to the north-east.
The strategic location of Inverness has led to many conflicts in the area. Reputedly there was a battle in the early 11th century between King Malcolm and Thorfinn of Norway at Blar Nam Feinne, to the southwest of the city.
Inverness had four traditional fairs, one of them being Legavrik (leth-gheamradh). William the Lion (d. 1214) granted Inverness four charters, by one of which it was created a royal burgh. Of the Dominican friary founded by Alexander III in 1233, only one pillar and a worn knight's effigy survive in a secluded graveyard near the town centre.
Medieval Inverness suffered regular raids from the Western Isles, particularly by the MacDonald Lords of the Isles in the fifteenth century. In 1187 one Donald Bane led islanders in a battle at Torvean against men from Inverness Castle led by the governor's son, Duncan Mackintosh. Both leaders were killed in the battle, Donald Bane is said to have been buried in a large cairn near the river, close to where the silver chain was found.Local tradition says that the citizens fought off the Clan MacDonald in 1340 at the Battle of Blairnacoi on Drumderfit Hill, north of Inverness across the Beauly Firth. On his way to the Battle of Harlaw in 1411, Donald of Islay harried the city, and sixteen years later James I held a parliament in the castle to which the northern chieftains were summoned, of whom three were executed for asserting an independent sovereignty. Clan Munro defeated Clan Mackintosh in 1454 at the Battle of Clachnaharry just west of the city. The Clan MacDonald and their allies stormed the castle during the Raid on Ross in 1491.
In 1562, during the progress undertaken to suppress Huntly's insurrection, Queen Mary was denied admittance into Inverness Castle by the governor, who belonged to the earl's faction, and whom she afterwards therefore caused to be hanged. The Clan Munro and Clan Fraser took the castle for her.The house in which she lived meanwhile stood in Bridge Street until the 1970s, when it was demolished to make way for the second Bridge Street development. The city's Marymass Fair, on the Saturday nearest 15 August, (a tradition revived in 1986) is said to commemorate Queen Mary as well as the Virgin Mary.
Beyond the then northern limits of the town, Oliver Cromwell built a citadel capable of accommodating 1000 men, but with the exception of a portion of the ramparts it was demolished at the Restoration. The only surviving modern remnant is a clock tower. In 1715 the Jacobites occupied the royal fortress as a barracks. In 1727 the government built the first Fort George here, but in 1746 it surrendered to the Jacobites and they blew it up.
Culloden Moor lies nearby, and was the site of the Battle of Culloden in 1746, which ended the Jacobite Rising of 1745-1746.
On September 7, 1921, the first UK Cabinet meeting to be held outside London took place in the Town House, when David Lloyd George, on holiday in Gairloch, called an emergency meeting to discuss the situation in Ireland. The Inverness Formula composed at this meeting was the basis of the Anglo-Irish Treaty.
The date of the first Inverness Gathering on the banks of the River Ness has been lost in the mists of time and will forever remain a mystery. What is known is that in 1822 the Inverness Courier reported that fundraising was taking place in the town to revive those ancient Games and to give the Capital of the Highlands a Highland Games that its townsfolk could be proud of.