Lieutenant Malcolm Fraser of the 48th Regiment of Foot asserted that on 23 August 1759, his detachment was brought under the command of Alexander Montgomery for an attack on a village near Saint-Joachim.
Fraser states in his journal:There were several of the enemy killed and wounded, and a few prisoners taken, all of whom the barbarous Captain Montgomery, who commanded us, ordered to be butchered in a most inhuman and cruel manner.
On one occasion while duelling in the bishop's garden in Derry, his opponent's first pistol-round shot off the tails of Montgomery's swallow-tailed coat.
Undeterred, Montgomery finished the duel sitting in a chair in order to conceal his bare posterior.
In 1797 he won a duel with a Donegal loyalist and was carried home in triumph to Convoy by the United Irishmen.
Mr. Montgomery has got to his Recommendation Two Boatmen, a Tidewaiter Surveyor of the Lough Swilley Barge and a Hearth Money Collection".
He died unmarried on 29 September 1800, at the age of 80, before the Acts of Union became law and on his tombstone in the churchyard of Raphoe Cathedral is inscribed: "Sacred to the memory of Alex Montgomery of Convoy who represented this once Independent county in Parliament for 32 years."