Zhang Heng

78 CE – 139 CE

Zhang Heng lived during the Han Dynasty, rising to prominence as an astronomer, writer, engineer and mathematician. He came to the imperial court and fashioned calendars for emperors, although he was not born of a royal family. He practised Confucianism and declined promotion to posts of greater responsibility, claiming he had little ambition. During his lifetime Zhang Heng invented a water-powered armillary sphere – a device used in astronomy – and mathematical equations to calculate the volume of threedimensional objects.

Emperor Qin Shi Huang was obsessed with achieving immortality, seeking the mythical elixir of life while taking poisonous mercury pills intended to make him immortal