At the time when Isaac Newton invented the first reflecting telescope and formulated his famous laws of motion and experiments were being made with Magdeburg hemispheres, when Louis XIV rebuilt the Palace of Versailles and Giovanni Battista Lulli launched French opera, Leopold I, who most notably shared a great passion for music with his archrival Louis XIV, ruled in Vienna. Music, opera, theatre, indeed the arts in general were deliberately (and justifiably, one might admit) employed as instruments for the display of power. For good measure, both rulers were also passionate dancers. But whilst Louis XIV merely consumed melody and harmony, the Cesarea Maestà turned his own hand to composition. Examples of the emperor’s musical accomplishments can be found today primarily in the Austrian National Library collections.