In 1697, Spain formally ceded to France control of the part of the island of Hispaniola that would become Haiti, naming it Saint-Domingue. Slavery in Saint-Domingue, France's most lucrative colony, was known to be especially brutal, with a complete turnover of the slave population due to death every 20 years. According to the historian Laurent Dubois, between 5 and 10 percent of slaves died every year due to overwork and disease, a rate that outpaced births. The dead were replaced by new slaves from Africa.