While many sources claim the Famous Grouse story began in 1800, the story of Matthew Gloag Sons didn't start with the Gloags at all. Rather, it began with the browns.
John Brown established his Perth grocery business in 1800 before moving the premises to Atholl Street seven years later. It was his daughter, Margaret, who married Matthew Gloag. She took over the family business from her father in 1824 and ran it until Matthew took control a little over a decade later.
It was in fact Margaret who acquired a license to sell wine and spirits (and snuff) in 1831; Matthew didn't join the business until 1835 when the name was changed to Matthew Gloag. Margaret died just five years later.