Celery is a historical crop, which dates from over 2000 years. It was already known to the ancient Egypt and Greek civilisations.
In the Ancient Greek mythology the nymph Kalypso tried to seduce Odysseus with a magic potion, based on celeriac. Even nowadays celeriac is meant to have romantic features!
In many cultures, over 2000 years celeriac has been known as a natural medicine. Since the Middle Ages celeriac is known to keep the water balance of the body and therefore stimulate urination. Nowadays, we also know of its general strengthening, blood clearing, cough relieving and water stimulating effect.
Actually, the celeriac which we know now - "Apium Graveolens var. rapaceum", also known as celery root, turnip rooted celery or knob celery - dates back from the 16th century when it had been developed from its celery ancestors. In fact, the common use of celeriac as a vegetable only started around the 18th century; before that it was mainly known as a medicine. In many ancient pharmacies we can still find "apium graveolens" as a medicinal herb.