The background to this battle can be found on the Scotwars website and of course Wikipedia. The set up followed the historic deployment, with Argyll's army deployed with the Campbell troops in the centre and regular troops on the flanks. These 'regulars' were veterans of the Marston Moor campaign and were expected to perform better than the levies used in earlier battles. The cavalry were placed on each flank. Montrose's army was outnumbered and had very few cavalry. An immediate attack was chosen as the best option, with the clans attacking the Campbells and the Irish taking on the regulars.
Montrose's attack was not well co-ordinated, the rough ground on the left slowed the Irish and hampered the clans; so MacColla's attack went in unsupported. This allowed the Covenanter's to concentrate their fire and the Royalists suffered heavy casualties. On Montrose's right, Ronald Og's Irish troops were preoccuied with the Covenant left wing cavalry, taking considerable time to drive them off to shelter beneath the walls of Inverlochy Castle. Fierce fighting between Campbell troops and
Montrose's clans continued and casualties rose on both sides.
Seeing the enemy's right wing cavalry moving to flank the attack on the centre, Montrose's bodyguard charged forward and caught the Covenanters unprepared. Although outnumbered the Royalists pushed back their opponents, causing even more confusion in their ranks.
Now their flank was secure the Irish on Montrose's left fired a volley and charged the Covenanter foot. The defensive volley was poor, most of the shot going high, and betrayed the nervousness of the supposedly experienced troops. The impetus of the Irish charge drove the Scots back, opening gaps which the Irish were quick to exploit. In no time at all order broke down completely and the Scots routed to the rear. Behind the Irish, the MacDonalds were trying to work around the flank, but progress was halted when the cavalry melee went against the Royalists. Although the Covenanters were pushed back and disorganised they so outnumbered their opponents that they managed to surround them. The small number of Royalists desperately sought to cut their way free; some were successful, but the standard bearer was captured. Amid some rejoicing the standard was carried to the rear by one of the young ensigns. This was to be the only real success of the day, because seeing the totally disorganised cavalry the MacDonald's charged and not waiting to cross swords the Covenanters routed.
The Irish on the left now reformed and moved to the flank of the Campbells. On the opposite flank the Irish had driven off the cavalry and the clansmen had at last routed the other Covenanter regiment. Both flanks of the Campbells were now 'in the air' and although they had forced Montrose's clansmen to fall back to reform, their position was desperate.
As one, all Montrose's units charged forward and the Campbells were overrun. A few, a very few, managed to hack their way to the temporary safety of Inverlochy Castle, but most died where they stood.
19th May, Northamptonshire
7 hours ago