Minerva was a Candian acoustic and archtop guitar brand name, distributed in the 1930s to 1940s by T Eaton of Toronto. There was also an Arthur Hensel Minerva model guitar - made in Toronto. Some of them have " Minerva hand made The R.S. Williams & Sons Co. Ltd.".  R.S. Williams & Sons Company was a musical instrument manufacturer founded in Toronto in 1855 which lasted until 1931.

Source: jedistar - Minerva page (1 June 2018)