Behind the plaque is a story of a boy who was bought from his master in the Congo by a Christian mission and then brought to Scotland in 1883 by the man now charged with his care.
Tom lived with his adoptive father Joseph Clarke and his adopted siblings from the Congo - brother Theo and sisters Vunga and Nkebani – in a house in Morningside Park.
In Scotland, it is likely Clarke, originally from Aberdeen, took Tom and the others on tour to promote the work of the mission, with audiences offered the chance to free an enslaved boy just like him for just £5.
Dr Christine Whyte, lecturer in global history at Glasgow University, said: “Public lectures were held by the mission across the country and the freed enslaved children from Africa would accompany them, to help to raise funds for the mission.
"The idea that these children were redeemed from slavery was emphasised with the public told that £5 was the amount needed to redeem a child from slavery in Africa.”
At one such meeting, a family from Aberdeen pledged £20 on the condition that two boys and two girls were freed.
Clarke travelled to Africa in 1879 with the Livingstone Inland Mission, set up amid the outpouring of public grief following the death of the Scots explorer in Zambia.
The Aberdonian was stationed at Palabala, where missionaries traded goods to free children, with bales of cloth sometimes exchanged for the liberty of girls and boys.
Children of high status locals also sent their children to the mission to be educated, with land sometimes gifted by elite members of the community for the cause.
Before mission life, accounts from enslaved children tell of them being moved through vast territories, often being marked or branded on their body as they passed between owners.
Dr Whyte said: “Very frequently, children were pawned, so they would be given as a security on a debt by people when they were really desperate.
“There were also instances when children were kidnapped during low lying local conflicts. In some places in the Congo during the time, children were sometimes trafficked to the east coast and then India.”
At the mission stations, children like Tom were educated and trained in skills such as printing and carpentry.
After being brought to the UK, great emphasis was also put on improving their English language skills, with many carrying out translation work and compiling dictionaries and grammar sets in their first language.
“This was regarded as important work for the mission, and important work for the Empire,” Dr Whyte said.
In Morningside, Tom’s sister, Vunga, who was given the English name Lena, became a talented linguist. After returning to the Congo, she recorded valuable testimonies of those victimised by the regime of King Leopold II, who embarked on a campaign of terror against the Congolese people as he and his private army sought to acquire ivory, minerals and rubber from the land.
Tom never returned home but died in Lochrin House in Gilmour Street, where he suffered ulceration of the stomach.
According to the plaque in Grange Cemetery, children from a local church laid the memorial to him.