From the seventeenth to the nineteenth century around ten million Africans were transported to Brazil as slaves - ten times as many as were shipped to the United States - yet the death rate in Brazil was so great that in 1860 Brazil's black population was half the size of that in the USA. Slavery was always contested: slaves fled from the cities and plantations to form refugee communities called quilombos; the largest, Palmares , in the interior of the northeastern state of Alagoas, was several thousand strong and stayed independent for almost a century.

But it was not until the nineteenth century that slavery was seriously challenged. The initial impetus came from Britain, where the abolitionist movement became influential just when Portugal was most dependent on British capital and British naval protection. Abolition was regarded with horror by the large landowners in Brazil, and a combination of racism and fear of economic dislocation led to a determined rearguard action to preserve slavery. A complicated diplomatic waltz began between Britain and Brazil, as slavery laws were tinkered with para inglês ver - "for the English to see" - a phrase that survives in the language to this day, meaning doing something merely for show. The object was to make the British believe slavery would be abolished, while ensuring that the letter of the law kept it legal.

British abolitionists were not deceived, and from 1832 to 1854 the Royal Navy maintained a squadron off Brazil, intercepting and confiscating slave ships, and occasionally entering Brazilian ports to seize slavers and burn their ships - one of history's more positive examples of gunboat diplomacy. The slave trade was finally abolished in 1854 but, to the disgust of the abolitionists, slavery itself remained legal. British power had its limits and ultimately it was a passionate campaign within Brazil itself, led by the fiery lawyer Joaquim Nabuco , that finished slavery off. The growing liberal movement, increasingly republican and anti-monarchist, squared off against the landowners, with Dom Pedro hovering indecisively somewhere in between. Slavery became the dominant issue in Brazilian politics for twenty years. By the time full emancipation came, in the "Golden Law" of May 13, 1888, Brazil had achieved the shameful distinction of being the last country in the Americas to abolish slavery.