Between 1640 and 1764, English courts moved from settling questions about land and mortgages to working out the rules for paper credit. Over the same years, the British slave trade grew from a trickle to more than thirty thousand people carried each year.
Greg · topic model of English case reports, set against SlaveVoyages data
Start with the trade itself. The dashed red line is the number of captives embarked on documented British-flagged voyages each year, smoothed to show the trend.
Through the 1640s and 1650s the numbers are small. From the 1660s, with the chartering of monopoly African companies, they begin to climb.
After 1698, when Parliament opened the African trade to separate traders, growth steepens. By the 1720s, British ships are embarking over twenty thousand captives a year, and by the early 1760s over thirty thousand.
Now the law. The blue line is how much of the reported case law concerns mortgages, measured as a topic's share of the corpus.
Mortgage law is the early frontier. It rises through the seventeenth century, peaks in the early 1690s, then falls away as the doctrine settles.
The green line tracks negotiable bills and notes: the instruments that let credit circulate as paper.
It rises later and overtakes mortgages around 1700. This is the period of the financial revolution: the Bank of England in 1694, and the Promissory Notes Act of 1704, which made notes transferable like bills of exchange.
Read together, the crossover around 1700 marks a compositional shift in what the courts spent their time on, and it coincides with the steepest phase of growth in British slaving.
The trade ran on credit: bills drawn on London merchants financed voyages and settled sales in the Americas.
A caution. The two sets of axes are scaled independently, so this figure shows timing and co-movement, not magnitude, and not causation.
Hover or tap anywhere on the chart to read the values for any year.