‘The Office of High Sheriff is the oldest secular Office in the United Kingdom after the Crown and dates from Saxon times’. This is the opening of an excellent brief history of the shrievalty, which can be found on the website of the High Sheriffs’ Association. It also explains how the role of High Sheriffs has evolved over the centuries.
The High Sheriff of Essex for 2018–19, Bryan Burrough, is said to be the 838th person to hold that office (there have been just seven female High Sheriffs of Essex – the first, Mrs Evelyn Ward-Thomas, was appointed in 1994). However, it is difficult to be sure of the exact number. From 1155, sheriffs can be identified from documents called pipe rolls, but up to that date it is necessary to extract information from a variety of sources, not all of them either clear or reliable. It seems likely, though, that the first recorded High Sheriff of Essex was Leofcild, appointed by King Edward the Confessor in 1042 or 1043. Thanks to his unusual name (it means ‘beloved child’) he can be identified as a man who held property in Essex and Suffolk before the Norman Conquest.
The next High Sheriff we know about is Robert FitzWymark, who was also prominent in King Edward’s reign. It is possible that he was High Sheriff under Edward and was reappointed by William the Conqueror in 1066. It also seems likely that he was succeeded as High Sheriff by his son Sweyn of Essex. At least ten other individuals have been identified as High Sheriffs of Essex up to 1155, although one is known only by the initial ‘N’; and there are seven more who might also have held the office.
Notable among the Norman High Sheriffs of Essex were Richard Basset and Aubrey de Vere, who in 1130 served simultaneously as High Sheriff for no fewer than eleven counties. This was exceptional, but it was normal during the Middle Ages for two counties to be joined together for shrieval purposes, so that Essex was combined with Hertfordshire between 1128 and 1567, as were Norfolk and Suffolk for a similar period.
There is a list of High Sheriffs of Essex on Wikipedia, but this has many shortcomings, especially regarding the years up to 1155. The website of the High Sheriffs’ Association has a complete list of the High Sheriffs of Essex since 1900.