 After the Act of Union 1800 , sometimes referred to as the Act of Union 1801 , the unreformed House of Commons was composed of 658 members , of whom 513 represented England and Wales . There were two types of constituencies ; counties and boroughs . County members were supposed to represent landholders , while borough members were supposed to represent the mercantile and trading interests of the kingdom . Counties were historical national subdivisions established between the 8th and 16th centuries . They were not merely parliamentary constituencies : many components of government ( including courts and the militia ) were organised along county lines . The members of Parliament chosen by the counties were known as Knights of the Shire . In Wales each county elected one member , while in England each county elected two members until 1826 , when Yorkshire 's representation was increased to four , following the disenfranchisement of the Cornish borough of Grampound . 
