The battle at Killiecrankie was a consequence of the Glorious Revolution. When William of Orange landed in England in November 1688, James VII of Scotland fled into exile, and a Convention in Edinburgh offered the Scottish crown to William and Mary in April 1689. But the transfer of power was not unanimous. John Graham of Claverhouse, Viscount Dundee -- a professional soldier who had served as James's military commander in Scotland -- refused to accept the new regime. On April 12, the day after the Convention offered the crown to William, Dundee raised the royal standard on Dundee Law and began gathering support for a Jacobite rising. His position was precarious. Most of Scotland was indifferent or hostile to the Stuart cause, and the hard-core Jacobites were mostly Highland clan chiefs whose warriors could be mobilized quickly but not kept in the field for long. Dundee needed a decisive victory to attract wavering supporters, and he needed it soon, before his clansmen went home.

The opportunity came when Mackay marched north to relieve Blair Castle, which had been seized by a Jacobite garrison. Dundee moved to intercept, assembling his forces -- roughly 2,500 Highlanders and 300 Irish reinforcements under Colonel Alexander Cannon -- on the slopes above the Pass of Killiecrankie. Mackay's force of between 3,600 and 5,100 men entered the pass on the morning of July 27, advancing along a track nearly three kilometres long with the river on their left and steep hills on both sides. It was a dangerous position: the Jacobites held the high ground, and the narrow track made both advance and retreat equally hazardous. Mackay recognized the danger and moved off the track, deploying his troops on the open ground at the northern end of the pass, facing the hillside where Dundee's men waited. His most experienced units, the Scots Brigade veterans who had served in the Dutch army, were placed on the left, where the field of fire was best. Then both sides waited. Dundee refused to attack while the sun was in his men's eyes, and the long summer evening stretched the tension across hours of mutual visibility.

The Highland charge was not a crude mob rush. It was a disciplined, rehearsed tactic designed to close the distance between attacker and defender so quickly that musket fire could not stop it. At sunset, Dundee gave the order. The Highlanders advanced in columns, absorbed three volleys from the Scots Brigade on the government left -- losing nearly six hundred men in the process -- then fired a single volley at fifty metres, dropped their muskets, drew swords and axes, and crashed into Mackay's line. The government troops were equipped with plug bayonets, a new weapon that had to be inserted into the musket barrel, rendering the gun useless for further firing. Inexperience with the bayonets and the terrifying speed of the charge left many soldiers defenseless. The regiments on the government right fled without firing a shot. Within minutes, Mackay's center and right had collapsed. Only the veteran Scots Brigade on the left held briefly before being overwhelmed. Balfour, their commander, was killed alongside Mackay's own younger brother James. The battle, from the moment of first contact to the rout, lasted approximately three minutes.

Dundee was shot in the final moments of the charge. The bullet struck him under his raised arm as he led the attack on horseback -- a wound that would prove fatal within hours. He may or may not have lived long enough to learn that his side had won; a letter reportedly sent under his name to King James describing the victory is generally considered a forgery, though it provides a useful summary of the action. Government losses were devastating: around two thousand killed, wounded, or missing, roughly half their force. But the Jacobite casualties were equally crippling in proportion. Between six and eight hundred Highlanders were killed or wounded, many of them from Lochiel's Camerons, the most reliable unit in Dundee's army. And the survivors, following Highland custom, halted their pursuit to loot the government baggage train, losing the momentum that might have turned a tactical victory into a strategic one. In 2004, a fragment of a hand grenade was found on the battlefield -- evidence of their first use in Britain, thirty years earlier than previously recorded. But the most significant artifact of Killiecrankie was the one that was lost: Dundee himself, the only Jacobite commander with the skill and charisma to hold the clans together. Without him, the rising stalled. An assault on Dunkeld in August was repulsed, and by the following spring the Jacobite army had dissolved. Mackay built Fort William to secure the Great Glen, and the Highland cause would not rise again until the Fifteen.