The islands were uninhabited , and the first settlement was founded in 1462 on the island of Santiago ( the main Island ) which was divided into two â capitaniasâ , Alcatrazes and Ribeira Grande . The first one failed and the main activity in Ribeira Grande was the exploitation of cotton farms . In 1462 , Portuguese settlers arrived at Santiago and founded a settlement they called Ribeira Grande ( now called Cidade Velha , to avoid being confused with the town of Ribeira Grande on the Santo AntÃ # o island ) .