Aug 15, 1645 Sir Lachlan Maclean lead the Macleans, fighting for Montrose, in the royalist cause against the Covenators army lead by William Baillie. The Macleans held were positioned early in on the central ground where the battle was expected to take place. Montros’ Royalists defeated the Covenators, killing 1/3 of them in battle.
A History of the Clan Maclean p170
en.wikipedia.org/wiki/Battle_of_Kilsyth
en.wikipedia.org/wiki/Clan_Campbell#17th_century_and_Civil_War