Her parents were of the landed gentry; William Hamilton Nisbet was a Scottish landowner, one of the few who owned large estates in Scotland.
[1] During her teens Nisbet's father became a Member of Parliament, and the family traveled to London, where she entered society via her grandmother, Lady Robert Manners.
[1] Following a short stint in London the couple left England on 3 September 1799 so that Bruce could take up his ambassadorial position; sailing from Portsmouth on HMS Phaeton.
During the two-month voyage they visited Lisbon and Gibraltar (as guests of Charles O'Hara), Sicily, Palermo, Messina and Tenodoes before arriving in Constantinople.
[clarification needed] The couple moved into the old French embassy (which had recently been vacated) which Mary Bruce then had decorated and where she hosted lavish parties.