'Donohoe Bertram, with somewhat of an Irish name and somewhat of an Irish temper, succeeded to the diminished property of Ellangowan. He turned out of doors the Reverend Aaron Macbriar, his mother's chaplain (it is said they quarrelled about the good graces of a milkmaid); drank himself daily drunk with brimming healths to the king, council, and bishops; held orgies with the Laird of Lagg, Theophilus Oglethorpe, and Sir James Turner; and lastly, took his grey gelding and joined Clavers at Killiecrankie. At the skirmish of Dunkeld, 1689, he was shot dead by a Cameronian with a silver button (being supposed to have proof from the Evil One against lead and steel), and his grave is still called the Wicked Laird's Lair...'
The Battle of Dunkeld occurred on August 21, 1689, in which Jacobites, supporting Catholic King JamesVII fought against Cameronian Royalists. William Cleland led the Cameronian forces to a major victory that came at the cost of his own life.
The Jacobite forces were mainly highland clans, with some Irish troops. Donahoe Bertram in the passage from "Guy Mannering" above has an Irish temper. The silver button may be playing to the feeling that diabolical powers were at work in the fierce battle that only a silver bullet could slay.