"Alexander Seton" also known as "The Cosmopolite", was a mysterious alchemist whose career spanned 1602-1604, when he was apparently killed by the ruler of Saxony for refusing to reveal the secret of the Philosopher's Stone. A Polish alchemist Michał Sędziwój visited him in prison and bribed a guard to let him escape. Alexander Seton allegedly died a few days later, having never revealed his secret.
years later, in 1618, another adept appeared in Europe, and again in
1666. I suspect the three men were the same person. It makes sense that a
man who is immortal would need to fake his death every few decades so
no one got suspicious.
In the video below Philip Coppens explores some of the places associted with the life of Alexander Seton.