[1] Walter Devereux's mother was Lady Dorothy Hastings, daughter of the 1st Earl of Huntingdon and Anne Stafford, said to have been a mistress of King Henry VIII.

[3] For his zeal in the service of Queen Elizabeth I on this and other occasions, he was made a Knight of the Garter on 17 June 1572 and was created Earl of Essex and Ewe, and Viscount Bourchier, on 4 May 1572.

[2][3][b] Eager to give proof of "his good devotion to employ himself in the service of her Majesty," Lord Essex, as he was now, offered on certain conditions to subdue or colonise, at his own expense, a portion of the Irish province of Ulster.

He arrested William Piers, who had been active in driving the Scots out of Ulster, and accused him of passing military intelligence to Sir Brian mac Phelim O'Neill.

[6] After encouraging Lord Essex to prepare to attack the Irish chief Sir Turlough Luineach O'Neill, apparently at the instigation of The 1st Earl of Leicester, the Queen suddenly commanded him to "break off his enterprise."

He also massacred several hundreds of Sorley Boy's following, chiefly women and children, who had hidden in the caves of Rathlin Island in the face of an amphibious assault led by Francis Drake and Sir John Norreys.