The Strangford Treaty was a treaty signed at Rio de Janeiro the 19th of February 1810 by the British and the Portuguese government, then in exile in its colony of Brazil. The treaty granted the British special commercial privileges, notably preferential tariffs of 15 percent on British goods imported into Brazil, in exchange for their defense of Portugal and its colonies during the Napoleonic War.Portugal also agreed to limit the importation of African slaves and to consider the abolition of the slave trade.