Which musicians and theorists advocated equal temperament in the early 18th century?

In the early 18th century, the German musician and theorist Andreas Werckmeister emerged as one of the most effective advocates for equal temperament.1

While the concept of equal temperament had been proposed by earlier figures—such as the theorist Vincenzo Galilei in 1581, the Chinese prince Zhu Zaiyu in 1596, and the French mathematician Marin Mersenne in 1636—it was not yet widely adopted for all instruments during the early 1700s.1

During this period, many musicians, including J.S. Bach, utilized systems that were approximations of equal temperament or modified versions of mean-tone temperament. Although Bach’s organ tuning was likely very close to equal temperament, he remained opposed to a strictly mathematical equality of intervals, and his famous work, The Well-Tempered Clavier, is believed to refer to a modified temperament rather than the modern equal temperament system.2