William Pynchon is Thomas' colonial descendant, born in Springfield, Essex, England on 11 October 1590. He married Anne Agnes Andrew about 1623. The family emigrated to New England on Winthrop's fleet of 1630, Anne dying soon after their arrival. A few years later, William married Frances Sanford of Dorchester. William was the founder of Springfield, Massachusetts and one of the Bay Colony's leaders until his publication of a book about justification and redemption, The Meritorious Price of our Redemption (1650) [Available in the, ahem, HyperArts BookShop.
From William Pynchon: Merchant and Colonizer (Connecticut Valley Historical Museum, Springfield, Massachusetts, 1961), by Ruth A. McIntyre, p.33:
The Massachussetts elders were shocked at a layman disputing the opinion of learned divines on such a question as the nature of Christ's sacrifice and man's justification.
With the printing of his treatise, The Meritorious Price of our Redemption...in London, [Pynchon] entered upon the exposition of his religious opinions which was to absorb his attention until his death. [...] Briefly, he questioned the accepted doctrine that Christ had actually endured the Hell torments of God's wrath to redeem men's souls. He had concluded after extensive study that the price of man's redemption was Christ's perfect obedience, of which His atonement was "the masterpiece." He could not conceive that God's wrath had forced the sinless Christ to bear the curse of suffering for man's guilt through imputation.
He returned to England to enjoy greater religious freedom and died at Wraysbury, England on 10 October 1662.