Henry IV cracks down on alchemy

Philosophers are banned from turning base metals into gold with this nervous proclamation

In all the years of English political history, few acts of parliament look odder than the Act Against Multipliers, signed into law by Henry IV on 13 January 1404. Instead of liberating the nation’s schoolchildren from the tyranny of times tables, this was actually an attempt to deal with a much more unsettling threat: the rise of alchemy.

Although the idea of alchemy – the belief that, with the right formula, a philosopher could turn base metals into gold – now seems absurd, it was one of the foundations of what became modern chemistry. Early scientists, from the Danish astronomer Tycho Brahe to Sir Isaac Newton, were often fascinated by alchemy. To many national governments, however, it seemed a threat to the natural order. For if an alchemist managed to make gold at will, he would not only undermine the entire economic system, he would become the most powerful man in the land.

So in early 1404, Henry IV – a man who knew a thing or two about overthrowing an established regime – decided to crack down on the alchemical threat. The Act Against Multipliers ordered that “none from hereafter should use to multiply gold or silver, or use the craft of multiplication; and if any the same do, they incur the pain of felony”. From this point onwards, prospective alchemists needed an expensive licence to pursue their experiments. Only in 1689 was the ban lifted, thanks to lobbying from one of the greatest scientists of the day – Robert Boyle, the father of modern chemistry, who was himself a keen but sadly unsuccessful alchemist.

A 14th-century French illustration shows alchemists at work. Alchemy was deemed to pose a real threat to those with power in the medieval world – as such, an act passed by Henry IV made the practice a felony