On the basis of information from several volumes of the History of Parliament, it is apparent that the history of the borough representation from Wales and Monmouthshire is more complicated than that of the English boroughs.
The Laws in Wales Act 1535 (26 Hen. VIII, c. 26) provided for a single borough seat for each of 11 of the 12 Welsh counties and Monmouthshire. The legislation was ambiguous as to which communities were enfranchised. The county towns were awarded a seat, but this in some fashion represented all the ancient boroughs of the county as the others were required to contribute to the members wages. It was not clear if the burgesses of the contributing boroughs could take part in the election. The only election under the original scheme was for the 1542 Parliament. It seems that only burgesses from the county towns actually took part. An Act of 1544 (35 Hen. VIII, c. 11) confirmed that the contributing boroughs could send representatives to take part in the election at the county town. As far as can be told from surviving indentures of returns, the degree to which the out boroughs participated varied, but by the end of the sixteenth century all the seats had some participation from them at some elections at least.
The original scheme was modified by later legislation and decisions of the House of Commons (which were sometimes made with no regard to precedent or evidence: for example in 1728 it was decided that only the freemen of the borough of Montgomery could participate in the election for that seat, thus disenfranchising the freemen of Llanidloes, Welshpool and Llanfyllin).
In the case of Breconshire, the county town was Brecon. The township of Llywel, eleven miles due west of Brecon, formed part of the constituency. There is no evidence to suggest any other boroughs actually took part in elections before 1597. The out boroughs then participating were Bulith now known as Builth Wells, Crickhowel or Crickhowell, Hay now Hay-on-Wye and Telgarth or Talgarth.
At some point between 1603 and 1715 the out boroughs ceased to participate in elections for the constituency. Until 1727 all the freemen of Brecon formed the electorate, but in 1727 the House of Commons ruled that only the resident freemen could vote. There had been about 180 electors in 1723 and 1727, but only 69 in 1744 after the basis of the franchise had been changed. There were about 100 voters between 1754 and 1790.
When registration of electors and an additional householder franchise were introduced in 1832 Brecon, still based on the town of Brecon, had the smallest electorate in Wales with just 242 registered voters. Even after the extension of the franchise in 1868, the number of voters only increased to 814.
After 1885 Breconshire was represented in Parliament by the single member county constituency, which included all the boroughs at one time in the Brecon constituency.
The Roman numerals after some names are those used in The House of Commons 1509-1558 to distinguish a member from another politician of the same name.
| Elected | Assembled | Dissolved | Member | Note |
|---|---|---|---|---|
| 1640 | 3 November 1640 | 5 December 1648 | unknown | Long Parliament |
| ... | 6 December 1648 | 20 April 1653 | unknown | Rump Parliament |
| ... | 4 July 1653 | 12 December 1653 | unrepresented | Barebones Parliament |
| 1654 | 3 September 1654 | 22 January 1655 | unrepresented | First Protectorate Parliament |
| 1656 | 17 September 1656 | 4 February 1658 | unrepresented | Second Protectorate Parliament |
| 1658/59 | 27 January 1659 | 22 April 1659 | unknown | Third Protectorate Parliament |
| ... | 7 May 1659 | 20 February 1660 | unknown | Rump Parliament restored |
| ... | 21 February 1660 | 16 March 1660 | unknown | Long Parliament restored |