 The European colonization of the Americas led to the Atlantic slave trade between the 1490s and the 1800s, which also contributed to the development of African intertribal warfare and racist ideology.Before the abolition of its slave trade in 1807, the British Empire alone (which had started colonial efforts in 1578, almost a century after Portuguese and Spanish empires) was responsible for the transportation of 3.5 million African slaves to the Americas, a third of all slaves transported across the Atlantic.The Holy Roman Empire was dissolved in 1806 by the French Revolutionary Wars; abolition of the Roman Catholic Inquisition followed.