Here's an interesting lecture about black musicians in Britain over the last few centuries (and earlier) -
Bridgetower – black musicians and British culture 1807-2007 -

...as far back as 1505 we have an African drummer working for James IV in Edinburgh, arranging a dance with dancers in black and white costumes for the Shrove Tuesday festivities. Black musicians are repeatedly mentioned in pageants, fairs and at least one tournament from the 16th Century onwards...