On Christmas Day 1817, the brig Dos Unidos, which also went by the name Yuyú, left the port of Cádiz, Spain. By then the project of the Cortes that had convened in that city had been defeated, and Ferdinand VII, whose restoration had been so fervently awaited, had returned to the throne. Almost immediately, he abolished the liberal Constitution of 1812. Sovereignty once more rested exclusively in the person of the king. The Cortes’s brief experiment with national sovereignty had not eradicated the practice of trafficking in human beings. So the Dos Unidos set sail for the coast of Africa to engage precisely in that trade. Its initial authorization for the journey was signed and dated the same week, and by the same minister, as the treaty with England that obligated Spain to end its slave trade. Neither the treaty nor this particular voyage, however, produced their intended outcome.

Forty-eight days after leaving Cádiz, the Dos Unidos arrived at the port of Bonny on the Bight of Biafra. By March 13, 1818, the captain had loaded 297 captive men, women, and children, and five days later, the vessel set sail for Cuba, where, calculated the captain, his human cargo might fetch upwards of one hundred thousand pesos fuertes. On the way, however, severe illness among the crew and captives forced a long stop at São Tomé. On April 29, they set sail again, planning to enter Caribbean waters at the passage between the islands of Martinique and Dominica and then make their way northwest to Havana. But on June 17–18, near the port of Les Cayes, Haiti (with only 171 of the original 297 captives still alive on board), a ship named the Wilberforce approached and fired. Though the vessel’s name was clearly English, the corvette belonged to the Republic of Haiti, one of several similarly named vessels: the Abolition de la Traite, the Philanthrope. The Haitian captain, his name perhaps hispanized in the Spanish record as Esteban Morete, made his intentions clear: he was taking the Dos Unidos to Port-au-Prince, because he had orders from his government – the southern Republic of Haiti – “to detain and seize any vessels carrying shipments of slaves.”