Background
Mainwaring was the eldest son of Sir George Mainwaring and Ann More, daughter of William More.
Mainwaring was the eldest son of Sir George Mainwaring and Ann More, daughter of William More.
He was awarded Bachelor from Brasenose College, Oxford on 7 July 1598 and Master of Arts on 15 June 1601. He began a rise to prominence working for Sir Thomas Egerton, in whose household he was steward from 1602 to 1617. John Payne Collier published records by Mainwaring relating to a performance of Othello for Queen Elizabeth at this period.
These were later recognised as forgeries, however.
A genuine connection with William Shakespeare was an attempt led by Mainwaring in 1614 to enclose lands at Welcombe near Stratford-upon-Avon, defeated by local resistance. He was declared of Cheshire when he was knighted at the London Charterhouse on 11 May 1603.
Mainwaring also and concurrently became a courtier, carver in the household of Henry Frederick, Prince of Wales from 1604. His financial position was improved when he became heir to Francis Wolley who died in 1609, despite litigation from family members.
He became notorious as the lover of Anne Turner, hanged in 1615 for her part in the murder case of Sir Thomas Overbury.
The relationship, seemingly tolerated by Anne"s husband Doctor George Turner who died in 1610, led to children but no marriage. Arthur Wilson claimed that she bought powders from Simon Forman to try to bring him to wed her. He was re-elected Member of Parliament for Huntingdon in 1625 and 1626.
From 1628 to around 1642 he served as Lieutenant of Windsor Forest.
In 1641 the forest was the scene of disorder and poaching of the deer, and he recommended firm action around Egham, which was however thwarted by local sympathies. He had objected at the beginning of the reign of Charles I to the East India Company"s gunpowder mills on the edge of Windsor Forest.
Later, in 1635, he was himself in the gunpowder business with Andrew Pitcairn.
Useless Parliament; Happy Parliament. 2nd Parliament of King Charles I]
In 1624, Mainwaring was elected Member of Parliament for Huntingdon for the Happy Parliament.