When was the supermarket founded by   Mary Ann Sainsbury's husband founded? 
Mary Ann Sainsbury: Mary Ann Sainsbury ("née" Staples; 30 June 1849 - 9 June 1927) was the wife of John James Sainsbury, the founder of the Sainsbury's supermarket chain. Sainsbury's:  Founded in 1869, by John James Sainsbury with a shop in Drury Lane, London, the company became the largest grocery retailer in 1922, was an early adopter of self-service retailing in the United Kingdom, and had its heyday during the 1980s.
1869