From 1808–34, the abolition movement progressively eliminated the slave trade with North America, but the Islamic Sokoto caliphate did its best to compensate. Founded in 1804 by a Sufist rebellion, this confederation of emirates became one of Africa’s largest polities and second only to the American South in its slave population, exploiting the networks established by the defunct European traders. South America continued to be the main destination for the trans-Atlantic slave trade. While Britain’s Cape Colony steadily expanded, and the French were establishing dominion in Algeria and Senegal, the continent’s greatest conqueror of the period was Muhammad Ali Pasha in Egypt, annexing Nubia, Sudan and Libya before waging war upon his Ottoman overlords. During the reign of Queen Ranavalona (1828–61) in the Merina kingdom of Madagascar, over 100,000 people are believed to have died through trials by ordeal, or over 20 per cent of the population, the main crimes being the practice of witchcraft or Christianity.