The French surrendered Mauritius and its dependencies (including the Chagos) to the UK in the 1814 Treaty of Paris. However, nothing precluded the transport of slaves within the colony, and so the ancestors of the Chagossians were routinely shipped from Mauritius to Rodrigues to the Chagos to the Seychelles, and elsewhere. In addition, from 1820 to 1840, the atoll of Diego Garcia in the Chagos became the staging post for slave ships trading between Sumatra, the Seychelles, and the French island of Bourbon, adding a population of Malay slaves into the Chagos gene pool.