Trinidad is reported to have been densely populated at the beginning of the colonial period. Although in 1510 Trinidad was said to have the only "peaceful Indians" along the whole South American coast, demand for slaves to supply the pearl-fisheries in nearby Isla Margarita led to them being declared "Caribs" (and thus, fair game for slavers) in 1511. As a consequence of this, Trinidad and Tobago became the focus of Spanish slaving raids, primarily to supply Margarita's pearl fisheries.
In 1530 Antonio Sedeño was granted a contract to settle Trinidad, with an eye toward discovering long-rumored El Dorado and controlling the trade in slaves. In 1532 he attempted to establish a settlement, but
was driven off the island following the Battle of Cumucurapo, (or The Place of the Silk Cotton Tree). He withdrew to Margarita, but he returned a year later and built a settlement at Cumucurapo (modern Mucurapo in what is now Port of Spain). After failing to attract more settlers to Trinidad, Sedeño was forced to withdraw in 1534.
In 1553 Juan Sedeño was authorised to settle Trinidad, but the contract
was never fulfilled. In 1569 Juan Troche Ponce de León built the "town of the Circumcision", probably around modern Laventille. In 1570 this settlement was abandoned. In 1592 Antonio de Berrio established the first lasting settlement, the town of San José de Oruña (the modern St. Joseph).
Sir Walter Raleigh, searching for El Dorado in South America, arrived in Trinidad on 22 March 1595 and soon attacked San José and captured and interrogated de Berrío, obtaining much information from him and from the cacique Topiawari.