Final answer:
The first performance of Handel's 'Music for the Royal Fireworks' featured an orchestra of about 100 musicians, suited to the grandeur of the event which celebrated the end of the War of Austrian Succession.
Step-by-step explanation:
Handel's Music for the Royal Fireworks was first performed with a large assemblage of musicians, significantly more than a typical ensemble. The first performance of this Baroque masterpiece took place on April 27, 1749, and featured an orchestra that was composed of about 100 musicians. This grand orchestra was assembled to match the scale and splendor of the event it accompanied - the royal fireworks display in London's Green Park, celebrating the end of the War of Austrian Succession and the signing of the Treaty of Aix-la-Chapelle in 1748. The band included a remarkable number of brass, woodwind, and percussion instruments, reinforcing the festive nature of the occasion.