Knights of the Shire
From the creation of the Parliament of England in mediaeval times each county of England and Wales sent two Knights of the Shire as members of Parliament to represent the interests of the county, until 1826 when the number of knights from Yorkshire was increased to four. With the Great Reform Act of 1832 different counties sent different numbers of knights to Parliament until the abolition of the seats in the Reform Act of 1884.
Middle ages 
The precursor to the English parliamentary system was a council of advisers to the King, consisting of noblemen and members of the aristocracy, and Knights of the Shire. Two Knights of the Shire were sent from each county. In 1264 this council evolved to include representatives from the boroughs (burgesses) and require that all members be elected (de Montfort's Parliament). The parliament gained legislative powers in 1295 (the Model Parliament). In the reign of Edward III parliament split into its current day format of two houses—the House of Commons and the House of Lords. The Knights of the Shire, together with the representatives from the boroughs, formed the House of Commons.
Until legislation in the fifteenth century the franchise for elections of knights of the shire to serve as the representatives of counties in the Parliament of England was not restricted to forty shilling freeholders.
Seymour, discussing the original county franchise, suggested "it is probable that all free inhabitant householders voted and that the parliamentary qualification was, like that which compelled attendance in the county court, merely a "resiance" or residence qualification". He goes on to explain why Parliament decided to legislate about the county franchise. "The Act of 1430, after declaring that elections had been crowded by many persons of low estate, and that confusion had thereby resulted, accordingly enacted that the suffrage should be limited to persons qualified by a freehold of 40s".
The Parliament of England legislated the new uniform county franchise, in the statute 8 Henry VI, c. 7. However the Chronological Table of the Statutes does not mention such a 1430 Act, as it was included in the Consolidated Statutes as a recital in the Electors of Knights of the Shire Act 1432 (10 Henry VI, c. 2), which amended and re-enacted the 1430 law to make clear that the resident of a county had to have a forty shilling freehold in that county to be a voter there.
Over the course of time a great number of different types of property were accepted as being forty shilling freeholds and the residence requirement disappeared.
Until the Great Reform Act of 1832, each county continued to send two Knights (apart from Yorkshire, which had its number of Knights increased to four in 1826). How these knights were chosen varied from one county to the next and evolved over time. The 1832 Act increased the number of Knights sent by some populous counties to as many as six.
Modern usage 
The term became obsolete in the later Reform Act of 1884, but is still used colloquially to refer to Members of Parliament who represent rural, or 'county' constituencies. With exceptions, they tend towards conservatism rather than radicalism.
See also 
- The text of the 1832 Reform Act
- Chronological Table of the Statutes: Part 1 1235-1962 (The Stationery Office Ltd 1999)
- Electoral Reform in England and Wales, by Charles Seymour (David & Charles Reprints 1970)
- The Statutes: Revised Edition, Vol. I Henry III to James II (printed by authority in 1876)
- The Statutes: Second Revised Edition, Vol. XVI 1884-1886 (printed by authority in 1900)