Short answers, pulled from the story.
Robert Dudley, 1st Earl of Leicester, was an English statesman born on the 24th of June 1532 and the lifelong favourite of Queen Elizabeth I from her accession in 1558 until his death on the 4th of September 1588. He served as Master of the Horse, privy councillor, and Lord Steward of the Royal Household, and was one of the dominant political figures of the Elizabethan era alongside William Cecil and Sir Francis Walsingham.
Amy Robsart, Robert Dudley's first wife, was found dead at the bottom of a flight of stairs at Cumnor Place near Oxford on the 8th of September 1560. A coroner's jury returned a verdict of accident. Most historians have considered murder unlikely; a theory first proposed in 1956 by Ian Aird, a professor of surgery, suggested that metastatic breast cancer could have caused her neck to break from a short fall or even from coming down the stairs.
The Kenilworth festival was a nineteen-day celebration staged by the Earl of Leicester in July 1575 at Kenilworth Castle in the English West Midlands, during a visit by Queen Elizabeth I. It featured a Lady of the Lake, a papier-mache dolphin with a small orchestra inside it, fireworks, masques, hunts, and bear baiting, and was interpreted as both a final bid for the Queen's hand and a request for leave to marry someone else.
Leicester's campaign in the Netherlands between 1585 and 1587 failed because of persistent underfinancing, Elizabeth I's orders to avoid decisive engagement with the Duke of Parma, quarrels with his own deputy Sir John Norris, and the defection of two Catholic officers with key fortresses to the enemy in late 1586. Leicester mortgaged his estate to £25,000 to fund the expedition personally and returned irredeemably in debt.
Leicester's Commonwealth was an anonymous libel written by Catholic exiles in Paris and printed in 1584. It depicted Robert Dudley as an atheist, hypocrite, and expert poisoner plotting to seize the English Crown. Smuggled into England, it became an underground best-seller and was translated into French the following year. It formed the basis of a literary and historical tradition that portrayed Leicester as a Machiavellian villain, a characterisation that dominated his reputation for centuries.
On the 21st of September 1578, Robert Dudley secretly married Lettice Knollys, widow of Walter Devereux, 1st Earl of Essex, at his country house at Wanstead. When Elizabeth I learned of the marriage nine months later, she was furious. Lettice Dudley was permanently banished from court, and the Queen never fully forgave the Earl, humiliating him in public and using his marriage as grounds to withdraw favour.