Much of Morgan's early life is unknown. He was born in Monmouthshire, but it is not known how he made his way to the West Indies, or how he began his career as a privateer. He was probably a member of a group of raiders led by Sir Christopher Myngs in the early 1660s during the Anglo-Spanish War. Morgan became a close friend of Sir Thomas Modyford, the Governor of Jamaica. When diplomatic relations between the Kingdom of England and Spain worsened in 1667, Modyford gave Morgan a letter of marque, a licence to attack and seize Spanish vessels. Morgan subsequently conducted successful and highly lucrative raids on Puerto Principe (now Camagüey in modern Cuba) and Porto Bello (now Portobelo in modern Panama). In 1668 he sailed for Maracaibo and Gibraltar, both on Lake Maracaibo in modern-day Venezuela. He raided both cities and stripped them of their wealth before destroying a large Spanish squadron as he escaped.