Short answers, pulled from the story.
Robert Devereux 2nd Earl of Essex entered the world on the 10th of November 1565 at Netherwood in Herefordshire. He was the eldest son of Walter Devereux 1st Earl of Essex and his wife Lettice Knollys.
Robert Devereux 2nd Earl of Essex received permission to accompany Leicester on a military apprenticeship in the Spanish Netherlands. He was appointed colonel-general of the English cavalry there and won the Battle of Zutphen in September 1586.
Queen Elizabeth I selected Robert Devereux 2nd Earl of Essex as Lord Deputy of Ireland in December 1598 to suppress Hugh O'Neill's resistance during the Nine Years War. The war cost £2,000,000 to suppress and represented eight times more than spent on all continental wars during her reign.
Robert Devereux 2nd Earl of Essex surrendered to Crown forces on the 19th of February 1601 and requested private execution rather than public beheading. He died on the morning of the 25th of February 1601 within the Tower of London after three strokes by executioner Thomas Derrick.
Robert Devereux 2nd Earl of Essex was a competent lyric poet who wrote poems such as Passion Discontented Mind and Muses no more but mazes. His lyrics were set to music by composers including John Dowland and Orlando Gibbons.