Canadian nobility. She married Sir Hugh Monatgu Allen,o ne of the managing directors of the Allan Line of steamships, in 1893. Together they had four children; Margurite (b.1895), Hugh (b.1896), Anna (b.1898) and Gwendolyn (b. 1900). Lady Allen her husband and two daughters Anna and Gwendolyn were sailing in first class on board the luxury liner the Lusitania when it was sunk by a German torpedo in 1915.

Marguerite, Lady Allan, 42, was from Montréal, Canada. She was born as
Marguerite Ethel Mackenzie and married Sir Hugh Montagu Allan, born 13 October
1860, one of the managing directors of the Allan Line of steamships, on 18 Oct
1893.

Prominent in Montréal society, Marguerite was sailing on the Lusitania with
Anna, 16, and Gwen, 15, to be reunited with family. Also traveling with them
were maids Emily Davis and Annie Walker, 30. During the voyage, Lady Allan was
seen playing cards in the smoking room with Sir Hugh Lane and Dr. Frederick
Pearson.

At the time of the torpedo's impact, Lady Allan was in the lounge with her
daughters, Sir Frederick Orr-Lewis, Dorothy Braithwaite, and Robert Holt. They
gathered on the portside where Sir Frederick's valet, George Slingsby, and Lady
Allan's maids joined them. One of the maids came with two lifebelts. Slingsby
gave his lifebelt to one of Marguerite's daughters. Dorothy separated from them
in the crowd and was last seen near lifeboat #14.

Marguerite jumped into the water with her daughters and Sir Frederick after
"saying that they would die together" . Both of her daughters died, but her
maids survived. Lady Allan's collarbone was broken and her back was injured
while in the water. It was previously suggested that a falling mast had broken
her collarbone, but this is unlikely presuming that Lady Allan was on the
portside of the ship, whereas the mast fell to starboard. Preston mentions,
however, that the force of the second explosion had thrown Lady Allan against a
rail and that might have caused the fracture.

Lady Allan was picked up by the Katrina (the SS Westborough in disguise) and
later taken to a hospital in Dublin

Both Lady Allen and her husband survived but the two daughters died in the sinking. Two years later her only son Hugh was killed in World War I, when his plane crashed over German territory. Her only surviving daughter Margurite passed away in 1942. Lady Allen and her husband ended up outliving all four of their children.