Sheriffs are the oldest office under the Crown and pre-date the Norman Conquest. At that time his duties included: keeping the King's peace and the collection of the taxes and rents etc. due to the King, as well as commanding the local militia.
After the Conquests the administration of the Shires was placed under the various earls, but as the work entailed increased the authority and duties shifted to the sheriff, further increasing his importance. By the 12th century the powers execised by the Sheriff became more routine, and by the 16th century his role had become largely ceremonial.
Until 1575 the Sheriff for Buckinghamshire was also the Sheriff for Bedfordshire, but after that date they became severed, and each County had its separate and distinct Sheriffs appointed to it.
The following web pages list the Sheriffs of Buckinghamshire from 1139 to 1739. The text of the pages is an exact transcription taken from the book "The History and Antiquities of the Town, Hundred, and Deanery of Buckingham" by Browne Willis, Esq. LL.D., London, 1755. The list is divided into sections headed by the monarchs name and their year of accession. The dates for each sheriff are expressed as 'Regnal Years' i.e. which years of the monarchs reign e.g. 17 Elizabeth means the 17th year of the reign of Queen Elizabeth I.
For further information the reader is referred to:
"The History and Antiquities of the Town, Hundred, and Deanery of Buckingham" by Browne Willis, Esq. LL.D., London, 1755
"The Buckinghamshire Sherriffs", by Hugh Hanley, Buckinghamshire Record Office, 1992