It wasn’t suThese days, we would call them proprietary blends. But in the late 1500s and early 1600s, individual alchemists called the medicines they cooked up in their labs ‘secrets’. And now, thanks to a study recently published in Heritage Science, we know a little bit more about the secrets of one alchemist in particular. It turns out that Tycho Brahe, mostly known for his study of astronomy, had his own basement laboratory for mixing medicines.

Now we know a little more about what type of elements he used.

Brahe’s famed observatory—located in his castle-like Uraniborg observatory on the island of Ven, in what is now Sweden—was dismantled following his death in 1601. But recently, a team of researchers from the University of Southern Denmark and National Museum of Denmark analyzed five shards rescued from what would have been the site’s old garden between 1988 and 1990. It’s believed those shards came from the basement alchemical laboratory.supposed to be there.