Alchemists believed that all things created on this earth were made of a single, tiny essence called the prima materia (first material). Through the manipulation of said prima materia, one could change the nature of any substance. Many alchemists also believed that metals ripened in the earth very similarly to plants, and that the final stage of metalic evolution was gold, after slowly going through various stages of transformations deep in the belly of the earth. Therefore, the alchemists reasoned, by attempting to change lead into gold through their art, they were not in fact practicing sorcery or Black Magic (most Medieval and Renaissance alchemists were staunch Christians), but changing things as nature changed them, merely speeding up the process.
Many began to travel the path of alchemy specifically due to this belief, hoping to acquire wealth, power, and renown through its practice. They sought the legendary Philosopher's Stone, a magical substance that would change base metals into gold, or grant the posesser immortality, or grant magical powers, or all of the above (the legends tended to vary a bit). Many instead found merely scorched fingers and dirty furnaces. However, along with the physical alchemy that was being practiced, a mystical and philosophical alchemy was being cultivated as well, one that even the Psychoanalyst Karl Jung would devote considerable time studying and writing about.
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