Relatively late in his career, Bonnie Scotland was relocated to Tennessee and became the leading sire in North America, with notable offspring including Hall of Famer Luke Blackburn and Belmont Stakes winner George Kinney.
Through his grandson Ben Brush, Bonnie Scotland's sire line produced multiple American Classic winners in the early 20th century.
Although Iago was a relatively obscure sire, Queen Mary came to be one of the most influential mares of her time, founding thoroughbred family 10-a.
According to horseman Henry Herbert, "he has the longest shoulder, deepest heart-place, best forehand, shortest saddle-place, and the most powerful quarters of any horse now before the public.
In 1873 at the advanced age of 20, he was purchased by William G. Harding of Belle Meade Stud in Tennessee, one of the major breeding operations of the time.