The crystalline element (S = sulphur) with its typical sulphur yellow colour is essential for all organisms. Like nitrogen, it is an important component of amino acids, proteins and enzymes. In case of deficiency in human, animal and plant organisms the protein metabolism is disturbed. Its effect as a preservative in wine was already known to the Greeks in ancient times and is mentioned by Homer (8th century BC), Cato the Elder (234-149 BC) and Pliny the Elder (23-79 AD). Until the 17th century, sulphur was traded as an "arcanum" (secret), i.e. a secret science known only to insiders and not accessible to the public. After repeated over-sulphurisation, the addition of sulphur to wine was briefly banned in some countries for health reasons and severely punished in the event of infringements.