Which spice was worth more than gold and grew on one small group of islands?

Nutmeg, which until the nineteenth century grew only on the Banda Islands - ten specks of volcanic rock in eastern Indonesia, total land area smaller than many cities. It was believed in Europe to ward off plague, and the markup between Banda and Amsterdam ran into the tens of thousands of per cent.

The Dutch East India Company decided a monopoly required owning the source. In 1621 Jan Pieterszoon Coen took the islands and destroyed the population - of perhaps 15,000 Bandanese, around a thousand survived; the rest were killed, starved, deported or enslaved, and the orchards were reassigned to Dutch planters worked by slaves. Coen's face was on Dutch banknotes into the twentieth century.

One island, Run, held out under English control, and in the 1667 Treaty of Breda the English traded their claim to it for a Dutch possession in North America called New Amsterdam. Trading Manhattan for a nutmeg island looks absurd now and was entirely rational then. The monopoly broke anyway when a Frenchman smuggled seedlings out in the 1770s and the trees turned out to grow perfectly well elsewhere.