Now that you know as much as you can about the composer, you must write him a letter offering your patronage. The letter should incorporate what you learned about him and also why you would like to hire him. Be kind and complimentary as you write, remembering that you are offering the composer a job. You may even want to mention any perks or benefits he can expect should he agree to your employment offer, perhaps like housing, pay, fame, marriage possibilities, etc.

Creatively incorporate each of these items into your letter as smoothly as possible:

his date of birth, at least by referring to the year
country where he was born and/or lives
musical style, forms, or pieces he's known for
influence on Baroque music or other composers
title(s) of sample piece(s) of music
your offer of patronage
reason(s) for your patronage