Zhu Zaiyu


Zhu Zaiyu was a Chinese mathematician, physicist, choreographer, and musician. He was a prince of the Chinese Ming dynasty. In 1584, Prince Zhu innovatively described the equal temperament via accurate mathematical calculation.
Zhu was born in Qinyang, Henan Province to an aristocratic family, the sixth-generation descendant of the Hongxi Emperor, the fourth emperor of the Ming Dynasty. Zhu inherited the title the Prince of Zheng in 1593, but quickly resigned it to his cousin. On the emperor's order, he was granted a new princely title in 1606, the year he delivered a set of ten musicological treatises to the court, establishing his scholarly merit. His posthumous name was
Zhu wrote on music theory and temperament, music history, dance and dance music, and several other works. Three music theory works in particular are associated with the ideas of equal temperament, the「律學新說」, 「律呂精義」, and 「算學新說」. His work has been described as "the crowning achievement of two millennia of acoustical experiment and research " and he is described as "one of the most important historians of his nation's music."
Zhu also wrote treatises on astronomy, physics, mathematics and calendrics, calculated the magnetic declination of Peking, the mass density of mercury and accurately described the duration of one tropical year to correct the Ming calendar.
Zhu's work on equal temperament didn't get any official recognition during his lifetime nor during the Qing dynasty. This was due to the Ming and Qing emphasis on classical scholarship and discouragement of ideas based on empirical observation rather than textual interpretations.