There have been 9 Ist Earls of Essex since 1139
Earls of Essex, 1st creation (c. 1139)
Geoffrey de Mandeville, 1st Earl of Essex (d. 1144)
Geoffrey de Mandeville, 2nd Earl of Essex (d. 1166)
William de Mandeville, 3rd Earl of Essex (d. 1189) (extinct)
Earls of Essex, 2nd creation (1199)
Geoffrey Fitzpeter, 1st Earl of Essex (d. 1213)
Geoffrey FitzGeoffrey de Mandeville, 2nd Earl of Essex (d. 1216)
William FitzGeoffrey de Mandeville, 3rd Earl of Essex (d. 1227) (extinct)
Earls of Essex, 2nd creation (1239)
Humphrey de Bohun, 1st Earl of Essex (d. 1275)
Humphrey de Bohun, 2nd Earl of Essex (d. 1298)
Humphrey de Bohun, 3rd Earl of Essex (d. 1322)
John de Bohun, 4th Earl of Essex (d. 1336)
Humphrey de Bohun, 5th Earl of Essex (1309–1361)
Humphrey de Bohun, 6th Earl of Essex (1342–1373)
Earls of Essex, 4th creation (1376)
Thomas of Woodstock, 1st Earl of Essex (1355–1397) (forfeit)
Earls of Essex, 5th creation (1461)
Henry Bourchier, 1st Earl of Essex (d. 1483)
Henry Bourchier, 2nd Earl of Essex (d. 1540) (extinct)
Earls of Essex, 6th creation (1540)
Thomas Cromwell, 1st Earl of Essex (1485–1540) (forfeit)
Earls of Essex, 7th creation (1543)
William Parr, 1st Marquess of Northampton (c. 1512–1571) (forfeit 1553; restored 1559; extinct 1571)
Earls of Essex, 8th creation (1572)
Walter Devereux, 1st Earl of Essex (1541–1576)
Robert Devereux, 2nd Earl of Essex (1566–1601)
Robert Devereux, 3rd Earl of Essex (1591–1646) (extinct)
CURRENT EARLDOM OF ESSEX ( the Cassiobury Earls )
Barons Capell of Hadham (1641)
Arthur Capell, 1st Baron Capell of Hadham (1604–1649)
Arthur Capell, 2nd Baron Capell of Hadham (1631–1683) (created Earl of Essex in 1661)
Earls of Essex, 9th creation (1661)
Arthur Capell, 1st Earl of Essex (1631–1683)
Algernon Capell, 2nd Earl of Essex (1670–1710)
William Capell, 3rd Earl of Essex (1697–1743)
William Anne Capell, 4th Earl of Essex (1732–1799)
George Capell-Coningsby, 5th Earl of Essex (1757–1839)
Arthur Algernon Capell, 6th Earl of Essex (1803–1892)
Arthur de Vere Capell, Viscount Malden (1826–1879)
George Devereux de Vere Capell, 7th Earl of Essex (1857–1916)
Algernon George de Vere Capell, 8th Earl of Essex (1884–1966)
Reginald George de Vere Capell, 9th Earl of Essex (1906–1981) (dormant 1981)
Robert Edward de Vere Capell, 10th Earl of Essex (1920–2005) (revived 1989)
(Frederick) Paul de Vere Capell, 11th Earl of Essex (b. 1944)
The heir presumptive is the present holder's fourth cousin once-removed William Jennings Capell (b. 1952).
The heir presumptive's heir apparent is his only son Kevin Devereux Capell (b. 1982)