Alexander Bannatyne Stewart was a retail draper in his father's firm, R. B. Stewart and John McDonald in Buchanan Street, Glasgow. In 1862 he married Fanny Stevenson, and they had four sons and four daughters.
He was also an amateur artist, and an enthusiastic collector. He bought Nocturne: Grey and Silver - Chelsea Embankment, Winter y205 when it was exhibited in Glasgow in 1879, but it was sold two years later, after his death.
MacLehose, James, Memoirs and portraits of one hundred Glasgow men, Glasgow, 1886, at http://gdl.cdlr.strath.ac.uk/100men/gm86.htm (accessed 2004.07.21).