Unfortunately, the history of slavery is almost as long as the history of human beings. It has existed in almost every human society in every part of the world. It was sometimes used as a way of subjugating a conquered enemy, though the primary motivation might be as simple as the desire for an unpaid workforce.

However, the term is most often used to refer to the Trans-Atlantic Slave Trade, lasting roughly from the 16th to the 19th centuries, in which people were captured in west Africa and transported across the Atlantic. It is sometimes called the African Holocaust or "Maafa", a term which roughly means holocaust in Kiswahili (a language spoken widely in east Africa).

Conditions on board the slave ships were so inhuman that many did not survive the voyage. This famous image shows the way slaves would be chained lying down on benches for perhaps 100 days, unable even to sit up.

slave ship layout

Unbelievably, this formation was known as "loose pack" as the slaves were lying on their backs. The alternative, "tight pack", which had the slaves lying on their sides, allowed the slaver to fit more slaves onto the ship. However it was eventually abandoned, not for humanitarian reasons but due to the brutal economic calculation that the higher mortality rate of "tight pack" meant that fewer slaves reached the new world alive than with "loose pack".

Once in America, Brazil or the West Indies, slaves were sold at auction to the owners of plantations of crops such as sugar, cotton and coffee. The ships would then return to Britain laden with these crops, then set out from Britain to Africa to begin the process again – the so-called "triangular trade".

Slaves were forced to work by the threat of brutal punishments if they refused, or even the threat that a family would be split up by selling one or more family members to another plantation. The children of slaves automatically became the property of the same plantation owner as their parents.

Question: what assumptions and beliefs made the slave trade possible? Did they exist before the slave trade or were they, at least in part, invented to justify it?

Question: how would you argue that slavery should be abolished to a plantation owner who said that it was economically necessary?

Question: as well as slavery, what other forms of racism are there? When and where have these existed? How much is racism a question of the law and how much a question of people's attitudes?