Towards the end of the 18th century, the British Army was charged with protecting new and lucrative interests in the Caribbean.
The islands of Jamaica, Barbados, Dominica, Saint Lucia, Saint Vincent, Trinidad and Tobago became known as the British West Indies, known for their sugar plantations.
This region is where the Army wanted to station their West India Regiments in the late 1790s and early 1800s.
White soldiers, unused to the region's climate, regularly fell ill, leaving garrisons dangerously undermanned.
This led to the decision to buy African slaves to fill those gaps.
When the Abolition of the Slave Trade Act of 1807 was passed, as many as 50% of Army regiments in the Caribbean included slaves.
The National Army Museum's archive in London holds official documents containing details about the formation of the West India Regiments.
"The records available tell us that the Army purchased about 13,400 slaves for these regiments [between 1795 and 1807] at the cost around £1 million," says Jasdeep Singh, the Research Curator at the National Army Museum.
"Looking at various years, it averages around £70 for the cost of one single slave.
"What the British soldiers didn't realise is that there were mosquitos carrying around Yellow Fever and a variety of tropical diseases.
"From Britain, there were policies sent forward to say 'Right, here are some supplies, here are some funds, go and purchase new Africans' – so purchase Africans from Africa, as slaves, and then recruit them into the West India Regiments."
One account from the early 19th century recorded the price of buying and clothing 272 African slaves who were made to work in the West India Regiments at a total cost of £32,600 - more than £2 million in 2020.
However, papers belonging to the British Governor of Jamaica from the time show there was discomfort in Britain about the use of slaves and a desire for change from the very top.
"In one of the letters, he cites His Majesty the King at the time, to say that we should try to wind down the numbers," Mr Singh said.
"It’s a gentle nod letter sent [to Britain], but actually, it does the opposite - there's almost an emergency purchase and it creates a spike in the numbers.
"When you start to get maybe 100 purchases for that regiment, you start to get 300 to 400 and those numbers really start to ramp up until 1807."
In the years after the slave trade was abolished, the role of those soldiers changed from having to protect colonial assets, to serving overseas.
"They went on to serve in west Africa – campaigns - and also won medals with clasps of Sierra Leone and Gambia.
"If we come a bit more into modern history, we know that they served in France in the First World War, they served in Palestine, they served in the Western Front.
"They served with honour, with distinction and loyalty at that time to the King," says Mr Singh.
"When we start to look at that service, we start to think about 'Why is some of that forgotten?'.
"The First World War narrative was largely dominated by the British Tommy.
"As a researcher, I've always said that remembrance and history starts with a name, and with a name we can go on to find any level of service.
"The complication with many of these men is their anonymity - so when we’ve got paintings, when we’ve got photographs, rarely are they named."
After first being raised in 1795 to support Britain's presence in the Caribbean, the West India Regiments remained a part of the Army until 1927, and at one point was comprised of 12 different regiments.
The unit was briefly re-formed in 1958, before being permanently disbanded four years later.