First published under the title The Theatre of the World, this is a captivating portrait of the crucible of magic, science and religion at the court of the doomed dreamer Rudolf II in Renaissance Prague. In the late 16th century the greatest philosophers, alchemists, astronomers, painters, and mathematicians of the day flocked to Prague to work under the patronage of the Holy Roman Emperor. The Mercurial Emperor is the enchanting story of Rudolf II, an emperor more interested in the great minds of his times than in the exercise of his immense power. Rarely leaving Prague Castle, he gathered around him a galaxy of famous figures: among them the painter Arcimboldo, the astronomer Tycho Brahe, the mathematician Johannes Kepler, the philosopher Giordano Bruno and the magus John Dee. Entranced, like Hamlet, with the new Renaissance learning, Rudolf found it nearly impossible to make decisions.Like Faust, he was prepared to risk all in the pursuit of magical knowledge and the Philosopher's Stone which would turn base metals into gold and prolong life indefinitely. But he also faced the threats of religious discord and the Ottoman Empire, along with a deepening melancholy and an ambitious younger brother. As a result he lost his empire and nearly his sanity but enabled Prague to enjoy a golden age of peace and creativity before Europe was engulfed in the Thirty Years' War. The Mercurial Emperor is an intriguing and dramatic human story. It is filled with angels and devils, high art and low cunning, talismans and stars, and offers a captivating perspective on a pivotal moment in the history of Western civilisation.