Charles Blount , 8th Baron Mountjoy Charles Blount ( pronounced " blunt " ) , 8th Baron Mountjoy and 1st Earl of Devonshire ( 1563 – 3 April 1606 ) was an English nobleman and soldier who served as Lord Deputy of Ireland under Queen Elizabeth I , then as Lord Lieutenant under King James I . Early life . The second son of James Blount , 6th Baron Mountjoy , Charles became the most notable of the later holders of the barony , inheriting the title in 1594 on the death of his unmarried elder brother William . The favour which his youthful good looks procured for him from Queen Elizabeth I of England aroused the jealousy of Robert Devereux , 2nd Earl of Essex , and led to a duel between the two courtiers , who later became close friends . Between 1586 and 1598 Charles spent a lot of time on the continent , serving in the Netherlands and in Brittany . He joined Essex and Sir Walter Raleigh in their expedition to the Azores in 1597 , along with his distant cousin , Sir Christopher Blount . ( Sir Christopher had married Essex ' s mother , Lettice Knollys , the Dowager Countess of Leicester , and he was afterwards executed for complicity in Essex ' s treason . ) Ireland . In 1600 Mountjoy went to Ireland as Lord Deputy in succession to Essex and , with the able assistance of Sir George Carew , brought the Nine Years War to an end with ruthless scorched - earth tactics in the stronghold of the rebel Hugh O ' Neill , 2nd Earl of Tyrone in Ulster . In July 1601 he had successfully ordered an amphibious landing at Lough Foyle , near Derry , which penetrated the north of the province and undermined the rebels . In the following December he defeated O ' Neill ' s Spanish allies at Kinsale , and drove them out of the country . On 30 March 1603 , six days after the death of Elizabeth and the accession of James I , O ' Neill made peace with Mountjoy , signing the Treaty of Mellifont . Mountjoy continued in office with the more distinguished title of Lord - Lieutenant ( 1603 – 1604 ) . He declared an amnesty for the rebels and granted them honourable terms , which caused some severe criticism from England . Later life . On his return to England , Lord Mountjoy served as one of Sir Walter Raleigh ' s judges in 1603 ; and in the same year James I made him master of the ordnance and created him Earl of Devonshire , also granting him extensive estates . Mountjoy took as his mistress Penelope Devereux , wife of Lord Rich and sister of Essex . After the execution of her brother in 1601 , Lady Rich ' s husband divorced her in the ecclesiastical courts . Mountjoy , by whom she had already had several children , married her on 26 December 1605 at Wanstead House in London , in a ceremony conducted by his chaplain , William Laud , afterwards Archbishop of Canterbury . This proceeding , carried out in defiance of canon law , was followed by the disgrace of both parties , who were banished from court by King James . The couple continued to live together as husband and wife with their children until his death a few months later . Blount died on 3 April 1606 and Penelope on 7 July 1607 . Penelope Rich ' s illegitimate children acknowledged by Charles Blount were : Legacy . Mountjoy left no legitimate children , and so the hereditary titles became extinct at his death .