Links between England's stately homes and slavery are to be researched to coincide with the 200th anniversary of the abolition of Britain's slave trade.
William Wilberforce was a key figure in the abolition of the slave trade
English Heritage, which maintains 400 properties, will look at the background of those dating from 1600 to 1840.
The organisation said it was staging the investigation to "reveal the fuller story of England's history", making it honest and fair.
Laws introduced in 1807 outlawed the slave trade across the British Empire.
English Heritage said it recognised its responsibility to reveal the possibly uncomfortable truth behind the history of some of England's great estates and houses, whose splendour could stem from wealth generated by the trans-Atlantic slave trade.
Commissioner Maria Adebowale said: "History must be honest and fair.
"The history of slavery needs to be properly recognised for the human misery it caused and the extent to which this appalling trade was used to improve state and individual wealth.
"The past can be painful, but English Heritage is committed to reflecting the rich history of all people in England."
The research is also aimed at revealing links with those who played a key part in the abolition of the slave trade.
The organisation outlined its plans at Kenwood House in north London, where a woman of dual heritage was brought up as part of the family of Lord Mansfield, a judge who ruled there was no legal backing for slavery in England - about 30 years before the trade was abolished.
Ms Adebowale said English Heritage also wanted to recognise the positive contribution the black community had made to England's economic and social history.
She said: "It's about recognising the fact that actually England has always been a diverse country, and we shouldn't believe the myth that it's only now that we have a multicultural society."
Any new findings unearthed about the history of the properties will be included in guide books or shown in displays at the houses.
Britain's involvement in the slave trade began in the 16th Century, when slaves were shipped to Britain from Africa to sell on to Spanish colonies, and the British slave trade began in earnest in the 17th Century.
The 1807 Abolition of the Slave Trade Act finally outlawed the trade throughout the British Empire and made it illegal for British ships to be involved in the trade.
But it was not until 1833 that slavery itself was banned throughout the empire.