Barbados was first settled by Amerindians, before being taken by Spanish slavers in 1492. The Amerindians were killed by European diseases before the arrival of British colonizers in 1627. The importation and growth of the sugar trade led to mass cultivation and the growth of plantations. These plantations were then populated with African slaves which British planters purchased from Dutch slave traders. One of the most prominent rebellions was Bussa's rebellion in 1816, which despite its lack of success raised awareness of the evils of slavery. Slavery officially ended in Barbados in 1834, though slaves would not be released from apprenticeships until 1838. Sir Grantley Adams founded the Barbados Progressive League in 1938 to fight for the right to vote, it is now known as the Barbados Labour Party. The Democratic Labour Party was formed 17 years later. Barbados gained its Independence by treaty on 30th November 1966.