Sir Robert Devereux, KG, PC, 2nd Earl of Essex

Robert Devereux, 2nd Earl of Essex, KG, PC, 10 November 1565 - 25 February 1601), was an English nobleman and a favourite of Elizabeth I. 

Politically ambitious, and a committed general, he was placed under house arrest following a poor campaign in Ireland during the Nine Years' War in 1599. 

In 1601, he led an abortive coup d'état against the government and was executed for treason.

Sir Robert is related to the grandchildren of Vernia Elvira Swindell Byars; 

http://thehennesseefamily.com/relationship.php?altprimarypersonID=&savedpersonID=&secondpersonID=I3&maxrels=30&disallowspouses=1&generations=30&tree=hennessee&primarypersonID=I50802