Alchemy was an ancient system built on the belief that all matter consisted of four elements: earth, air, fire, and water. We know now that it’s a lot more complicated than that, but at the time it was believed that if you combined these elements in the correct, and as yet unknown, order, you could make anything. Even gold. Simply put, the king banned chemistry to keep anyone from getting richer than he was.

Henry’s anxiety was based on the fact that he had a lot of detractors. He seized the crown from his cousin, Richard II, five years earlier, and Richard (unsuccessfully) tried to exile him. The years that followed were a blur of uprisings, border challenges, and foreign pressure. From Wales to York and from the Scots to the French, rebellions popped up often. Now, Henry feared that someone might be able to make gold and devalue the treasury. Or worse, bankroll one of his challengers.

In the end, it wasn’t gold that felled Henry—it was his health, as he died of natural causes. Alchemy never achieved its mystic promise, but it didn’t disappear with the ban. Instead, it evolved: Isaac Newton believed in it. Robert Boyle—the founder of chemistry—practiced it too. Alchemy boiled down to studying how things interact with other things. What began as mythical transformation slowly became systematic experimentation. The act was repealed in 1688.

Sign up for our Today in History newsletter and get stories like this and many others delivered to your inbox each morning.