A chapel to Santiago rises at the port where the ships loaded

In 1480 the Portuguese built a chapel to Santiago at Elmina, on the coast of what is now Ghana. Santiago is Saint James the Greater, patron of Iberian Catholics, shown in Spanish devotional prints on a white horse with a raised sword, riding over the bodies of Moors. Elmina became one of the great points of embarkation for captives shipped to the Americas, so the image was standing at the door of the slave trade more than a decade before the crew of the Santa Maria set foot on Hispaniola. Africans met this saint at home, on their own ground, and had generations to make their own sense of him. In Dahomey the god of iron and war was Gu, whose emblem was a curved blade called the gubasa. A sword raised in a print and a blade raised in a shrine were close enough to be read together. Haitian Vodou later knew the figure as Sen Jak, senior brother of the Ogou spirits.

In April 1482 a Portuguese squadron under Diogo Cao was working its way south along the African coast in search of a sea road to India when it came on the mouth of a very large river. Cao took his ships in and landed at Mpinda, the chief port of the kingdom of Kongo. People of the coastal province of Soyo told him that the ruler of the country lived far inland, at Mbandza Kongo. Cao belonged to the Order of Christ, the Portuguese crusading order that Prince Henry the Navigator had directed and that paid for these voyages. Travelling inland the Portuguese found six provinces, well watered farmland, cattle herds, cloth woven locally, streets lined with orange and lemon and pomegranate trees, and a royal court whose ceremony they compared with their own. This meeting opened three centuries of traffic between Portugal and Kongo. The same coast later supplied a large share of the people shipped to Saint-Domingue, the colony that became Haiti.

En Bas Saline sits about a kilometre inland from Limonade Bord de Mer on the north coast of Haiti. Researchers including Kathleen Deagan have identified it as the village of the cacique Guacanagari and as the ground on which La Navidad stood. The case is circumstantial and rests on several strands at once. The site is unusually large and laid out in the pattern of a chief's town. It holds European objects, among them metal aglets, the small tips laced onto Spanish clothing, and bones of animals that were never native to the islands. Its distance from the shore matches contemporary descriptions of where the Santa Maria went aground. The mixture is what makes the place valuable. European material appears inside a Taino village that was still running as a Taino village, so the first weeks of contact can be read in the ground and not only in the admiral's journal. Keegan and Hofman call it a bridge between the pre-Columbian and colonial worlds.

By the 1490s the enslaved people held in Sicily were more often black than white, and the notaries who wrote them into contracts used the phrase sclavi negri. Sicily had been a slaveholding society for centuries under a succession of rulers, and the people held there came from wherever war and raiding could reach: the Balkans, the Black Sea, North Africa, the lands south of the Sahara. What changed in this decade was the proportion. Captives moving north on the caravan routes across the desert, together with Portuguese trading on the Atlantic coast, arrived in numbers that tipped the balance. Eltis and Richardson use Sicily as a marker for a shift running through the whole Mediterranean world. The timing is the part to hold. The identification of slavery with African skin was already settled in southern Europe in the 1490s, before a single sugar estate existed in the Americas. The Caribbean inherited that assumption ready made.