Alchemical symbols were first used by Greek, Syrian and Egyptian writers about the fifth or sixth century AD. The abbreviation of words in the form of signs and symbols saved them from constant repetition. Signs and symbols were adopted and developed by medieval Arabic and European writers, alchemists, astrologers, apothecaries and natural philosophers. In the seventeenth and eighteenth centuries tables of parallel systems were frequently published. With the advance of modern chemistry and physics their use became largely obsolete.