In 1915 Mark Harris established Mark Harris Manufacturing in what was then Salisbury, using the trade name Atlas. In 1920 he sold his shares to the British South Africa Company. In 1924, the name was changed to The Rhodesian Milling and Manufacturing Co., Ltd.
The Bulawayo Mill was expanded in 1930 to accommodate greater production and had a railway running through the business. The mill also had its own laboratory to check on the quality of the product. The Salisbury plant was located on two acres with a railway track running by it, allowing 15 trucks to load. The Salisbury mill was devoted too maize production.
One of its most famous products was the ‘Gloria’ flour, was released in 1920. However, the company also handled farm produce, including ground nuts, or monkey nuts. The company also produced soaps including Rainbow and Reliance brand soaps.
In 1956 the Rhodesian Milling and Manufacturing Company purchased Harris Brothers & Co.