After enduring persecution at the hands of the Spaniards, he escaped to England in 1568;[1] his wife, a daughter Margaret, and her husband Michael Boudean accompanied him.
The son-in-law, Boudean, soon died, leaving a son Peter, and the daughter married a second husband, John Money, an English merchant.
[2] At Haarlem, William married the deaf and dumb daughter of Peter Cromling, a Dutch merchant there, which brought him a dowry of £60,000.
In 1606 the two brothers entered into partnership with their brother-in-law John Moncy to continue and extend the elder Courten's silk and linen business.
[2] William's operations were not confined to his London business: he built ships and traded to Guinea, Portugal, Spain, and the West Indies.
With a view to profiting to the fullest extent by his discovery, he petitioned in 1625 for the grant of all unknown land in the south part of the world, which he called 'Terra Australis Incognita'.
He sent two ships with 1850 persons on board to Barbadoes, under Captain Powel, who, on his arrival, was nominated governor by Courten and the Earl of Pembroke; but the speculation proved disastrous.
[2] Losses of ships and merchandise sustained at the hands of the Dutch in the East Indies, after the Amboyna massacre, combined with the injustice he suffered in Barbadoes injured Courten's credit at the opening of Charles I's reign.
To satisfy his claim on the estate of Sir Peter, Boudean now seized the whole property of the firm of Courten & Moncy in Holland.
William, the younger, found his father's estate seriously embarrassed by the proceedings of his cousin Peter Boudean, who declined to surrender any of the Dutch property.
The Earl of Bridgewater declined to assist Courten further; the disturbed state of the government rendered any help from that quarter out of the question; and in 1643 bankruptcy followed.
Proceedings were also begun in Holland against the Dutch East India Company for compensation for the ships lost in 1641; the English courts of law and parliament were constantly petitioned for redress until the end of the century, but the greater part of the enormous wealth of Sir William Courten never reached his descendants.
In August 1660 the privy council heard evidence in support of the claims of Courten's grandson to the ownership of the Barbadoes, but did not deem the proof sufficient.
[2] Famed physician and collector Hans Sloane acquired (by bequest, conditional on paying of certain debts) Courten's grandson's (also William 1642–1702) cabinet of curiosities in 1702 and later donated much of it to the British government.