[ Gentleman's Magazine ]
The Gentleman's Magazine was an important and influential monthly magazine in the 18th and 19th Centuries; it began in 1731, ceased regular publication in 1907, and shut down completely in 1922.
The February of 1826 issue featured a substantial obituary of Rear-Admiral James Macnamara, whose place in the history of the Newfoundland dog is secured by his having killed, in a duel, an army colonel with whom he got into an argument when the two men's Newfoundland dogs began to fight.
This incident, from 1803, is treated at some length here at The Cultured Newf; the trail begins right here.
The obituary mentions the Newf-related incident only once:
On the 6th April, 1803, Captain Mcnamara being in Hyde Park with his Newfoundland dog, the latter began fighting with one belonging to a Lt-Col. Montgomery, who alighted from his horse to separate them. High words ensued between their respective owners, which led to a duel the same evening at Chalk Farm. The parties were both wounded, the Colonel mortally.
The obituary goes on to recount the trial and aquittal of Capt. Macnamara before treating the rest of the Captain's life and military career.