London's mayor apologized Wednesday for his city's role in the African slave trade, to mark the 200th anniversary of the law that abolished the slave trade in Britain's colonies. Mayor Ken Livingstone delivered the apology before the March 25 anniversary of the Parliamentary act that abolished the slave trade - but not slavery itself. The Royal Africa Company, based in London and founded in 1672, was granted a monopoly in the slave trade. After its charter was revoked in 1698, Bristol and then Liverpool eclipsed London as slave trading centers, sending ships to Africa to acquire slaves to be sold in the New World. "I invite all representatives of London society to join me in ... formally apologizing for London's role in this monstrous crime," Livingstone wrote in The Guardian newspaper.