Robert Devereux, second Earl of Essex, is yet another example of how the Tudor and allied families occupied a tangled web of connections. Robert's maternal great-grandmother was Mary Boleyn, sister of Anne Boleyn, who was the mother of England's Queen Elizabeth I. His stepfather and godfather, Robert Dudley, was Elizabeth's favorite for most of her life. Thus, Robert Devereux grew up in and around the court of Elizabeth. His natural father died when he was very young, and his mother remarried, to Dudley.

Robert grew up on his father's estates in Staffordshire and Wales. He was educated at Trinity College, Cambridge. He was close to this stepfather, and even served under him in the Netherlands. Upon his return he was a grown man and was officially introduced to Elizabeth's court. His eloquence, wit, and good looks made him an instant favorite with the queen. He even replaced his own stepfather as Master of the Horse, a position that put him in close, daily contact with the queen.

In 1590 he married Frances Walsingham, who was the daughter of one of Elizabeth's most powerful and important ministers, Sir Francis Walsingham. The couple had several children. Robert's greatest difficulty in managing his career at court had to do with his relying on the queen's personal devotion to him to excuse a variety of inappropriate behaviors. He sometimes displayed a distinct lack of respect for the queen, and on one occasion, out of frustration, Elizabeth cuffed Robert on the ear. His response was to draw his sword on her.

When his father died, Elizabeth bestowed upon Robert a number of his father's honorifics and entitlements. In 1589, he participated in the English Armada, led by Sir Francis Drake, which sailed to Iberia to defend lands England wished to claim over Spain. The attempt failed, and he returned to England. He continued with his military career for several years, but also was curious about voyages of exploration. He joined Sir Walter Raleigh, serving as his second command on a voyage to the Azores. Even many miles away from his sovereign, he continued to defy her orders.

Upon his return, he persuaded Elizabeth to grant him the title of Lord Lieutenant of Ireland. He led the largest expeditionary force ever sent to Ireland, in an attempt to put down rebellion. Like many of his other military misadventures, his plan failed miserably. Against Elizabeth's orders, he developed a habit of knighting a great many soldiers, so many that his advisors claimed the only time he would draw his sword was to create a knight. By this time, Elizabeth had ordered Robert never to return to England. However, he did so in September 1599 and presented himself in her bedchamber so early in the morning she had not time to dress. She immediately had him confined to his rooms in Nonsuch Palace, stating that "an unruly beast must be stopped of his provender."

Most of his titles and powers were stripped from him upon his release, with Elizabeth issuing a strong warning for him to retire to private life and keep away from her court, politics, or the military. Some of Elizabeth's advisors pushed further, knowing Robert could not cease his bad behavior even if he wanted to, and in June 1600 he was returned to confinement. When he was freed again in August, he was without any income or position to maintain his lifestyle. Early in 1600, he began to stock arms and fortify his home with soldiers and other followers. Once organized, he and his supporters marched into London in an effort to demand audience with the queen. He found no support in London and quickly made a retreat. within a week he was arrested and tried on charges of treason.

He was found guilty and beheaded. It reportedly took three blows of the axe to dispatch him. Two years after his death (and that of Elizabeth) the English composer John Dowland published his song, "Can she excuse my wrongs with virtue's cloak?" (1597) as "The Earl of Essex, his galliard."