She was a member of the Simmons family who published radical works in London in the 17th century.

They had children together including Samuel Simmons[1] Mary was the person named as the administer of his affairs.

[2] Thomas Brooks's Anexichniastoi ploutoi tou Christou (The unsearchable riches of Christ) was printed by Mary Simmons in 1655[3] and her son Samuel was sent to the Merchant Taylors School until 1656.

In 1667 he notably added his name to his first book to the Stationers' register and that was Paradise Lost.

Her son Samuel Simmons committed himself to publish it as a single work and Mary transferred the rights to him in 1673.