Who was Scarlatti's first patron?

The correct answer is Queen Christina of Sweden. Domenico Scarlatti, the renowned Baroque composer and keyboardist, received significant early support and patronage from Queen Christina during his time in Rome. Christina, known for her keen interest in arts and culture, invited various artists and musicians to her court, making her an influential figure in the musical landscape of the time.

Scarlatti's relationship with Christina allowed him to further develop his unique style, particularly in the realm of keyboard music, where he created numerous sonatas that showcase his innovative harmonic language and virtuosic technique. Christina's patronage was pivotal in promoting Scarlatti’s work, laying the foundation for his later career.

This enhances the understanding of how important patronage was in the Baroque period, as it often determined the success and direction of a composer’s work. The support that Scarlatti received from Queen Christina contrasts with the other figures listed in the choices, who either came later or were not significantly connected to Scarlatti's early career.