The Zong was an overloaded slave ship which crossed the Atlantic in 1781.
The ship missed its destination in the Caribbean and had to spend an extra three weeks at sea.
Drinking water was growing short and sickness had spread.
Approximately 131 captive African people were thrown overboard by the slavers.
The crew were brought to trial in 1783, although the case was heard as an insurance dispute not a murder trial.
The case came to symbolise the horrors of the Middle Passage and strengthened the abolition campaign.