page_title: Timeline of chemical warfare
section_title: In prehistory and myth
hierarchical_section_title: Timeline of chemical warfare / In prehistory and myth
context_page_description: Chemical warfare is "the use of toxic chemicals in battle." The precise date of the first instances of chemical warfare is unknown, but scholars speculate that smoke have been used as an irritant in both battles and for hunting in prehistoric times. The first records of chemical warfare come from accounts of India in the fourth century BC, when Indian archers dipped their arrows in snake venom. In the same period, the use of smoke against enemies digging tunnels was first recorded in Greece and China. The next several centuries witnessed more and more sophisticated applications of toxic smoke and poisons in warfare.
  In the Middle Ages and the early modern period, chemical warfare advanced along with the development of chemistry. In 1456, during the Siege of Belgrade, an alchemist created poison clouds by burning rags that may have contained chlorine gas. In the fifteenth century, Leonardo da Vinci designed explosive shells filled with arsenic and sulfur for use against ships, and in the nineteenth century, Thomas Cochrane advocated the use of burning sulfur as a naval weapon.
caption: Heracles and the Hydra, (c. 1475) by Antonio Pollaiuolo (Galleria degli Uffizi).
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