Rhode Island was one of the original Thirteen Colonies. It became very important to the economy because of the slave trade, and more slaves were taken to the thirteen colonies through Rhode Island than any of the others in the 18th century. Slavers would send ships from Newport to buy slaves from Africa and make money by trading goods with others involved in slavery. Rhode Island became a state (the last of the thirteen to agree to the new United States Constitution) in 1790.