John Newton was a key figure in the abolitionist movement
The tomb of an anti-slavery campaigner who wrote the hymn Amazing Grace is among monuments given new protection because of their slave trade links.
John Newton's tomb at Olney, near Milton Keynes, is one of four to be newly awarded Grade II listing.
Another 21 are having their listing changed or upgraded to mark the International day for the Remembrance of the Slave Trade and its Abolition.
The government said they should be preserved for future generations.
The headstone erected in Watford for George Edward Doney, a Virginian slave who came to Britain and worked for the Earl of Essex, will also be protected.
As will the tomb at Windermere, Cumbria, of Rasselas Belfield, who was born into slavery in Ethiopia but later escaped from a slave ship and gained his freedom.
The fourth monument, in Abney Cemetery, Stoke Newington, north-east London, to be listed commemorates Joanna Vassa, the daughter of Olaudah Equiano - England's foremost black abolitionist.
These new listings and upgrades show the close and continuing historical and social links that much of our heritage has to the history of slavery
Monuments upgraded in importance include Picton House, Kingston upon Thames, which was bought in 1795 by slave Cesar Picton who went on to become a successful coal merchant.
The statue in Bloomsbury Square, London, of MP Charles James Fox, who introduced the resolution on the abolition of the slave trade which was passed by Parliament in 1807, has also been upgraded.
The status changes are part of an English Heritage project started in 2006 to review listed buildings and acknowledge historic links to transatlantic slavery and the abolitionist movement.
Culture Minister Margaret Hodge said the buildings and monuments represented different and important aspects of the history of the slave trade and should be preserved for future generations.
She added: "These new listings and upgrades show the close and continuing historical and social links that much of our heritage has to the history of slavery both in this country and from around the world."
Peter Beacham, English Heritage's protection director, said it was important to remember the "extraordinary and moving stories" the monuments and buildings represented.
"Listing is not just about protecting special buildings, it can help us acknowledge and understand our shared history," he added.