Admiral Sir John Hawkins of Plymouth, a notable Elizabethan seafarer, is widely acknowledged to be "the Pioneer of the English Slave Trade". In 1554–1555, Hawkins formed a slave trading syndicate of wealthy merchants. He sailed with three ships for the Caribbean via Sierra Leone, hijacked a Portuguese slave ship and sold the 300 slaves from it in Santo Domingo. During a second voyage in 1564, his crew captured 400 Africans and sold them at Rio de la Hacha in present-day Colombia, making a 60% profit for his financiers. A third voyage involved both buying slaves directly in Africa and capturing a Portuguese ship with its cargo; upon reaching the Caribbean, Hawkins sold all the slaves. On his return, he published a book entitled "An Alliance to Raid for Slaves". It is estimated that Hawkins transported 1,500 enslaved Africans across the Atlantic during his four voyages of the 1560s, before stopping in 1568 after a battle with the Spanish in which he lost five of his seven ships. The English involvement in the Atlantic slave trade only resumed in the 1640s after the country acquired an American colony (Virginia).