William Shakespeare's history is really very unknown although many people write volumes and volumes about this man's life. However, biographers feel the ability to do so because he has so many clues in his writings as to who he may have associated himself with. Here are some folks to consider:
Queen Elizabeth (partron) - she loved the theatre and helped fund the acting of the Lord Chamberlain's Men, Shakespeare's acting group.
King James (patron) - he succeeded Elizabeth and continued to support Shakespeare.
Christopher Marlowe (associate/rival) - this is an assumed relationship by their writing. He wouldn't think very highly of Shakespeare.
Richard Burbage, Cuthbert Burbage (associates) - If you are doing some kind of business writing assignment, learn about these guys. There were men who owned a large portion of the original Globe Theater.
Robert Greene (playwright/critic) - this man didn't care for Shakespeare's work.
Initially, Shakespeare's first London employer would have been Philip Henslowe, the businessman and owner of the 'Rose' theatre on Bankside, where Shakespeare's 'HenryV1' was first performed.
Following the success of his playwrighting, his second employer may well have been Lord Hunsdon, the Lord Chamberlain, who, in 1594, offered Shakespeare a one eighth part in his new company, the 'Lord Chamberlain's Men'. This partnership meant that its owners would share the profits, it also meant they would have to share the costs of any new production. Shakespeare agreed.
His final employer, would most probably have been King James 1, who, after his coronation in 1603, almost immediately offerred his patronage to Shakespeare's acting company, re-naming it the 'King's Men'.