The earliest known parliament met at Kilkea Castle near Castledermot, County Kildare on 18 June 1264, with only prelates and magnates attending.

[5] The clerical proctors elected by the lower clergy of each diocese formed a separate house or estate in until 1537, when they were expelled for their opposition to the Irish Reformation.

Unable to implement and exercise the authority of the Parliament or the Crown's rule outside of this environ, and increasingly under the attack of raids by the Gaelic Irish and independent Hiberno-Norman nobles, the Palesmen themselves encouraged the Kings of England to take a more direct role in the affairs of Ireland.

Despite an era which featured royal concentration of power and decreasing feudal power throughout the rest of Europe, King Henry VIII over-ruled earlier court rulings putting families and lands under attainder and recognised the privileges of the Gaelic nobles, thereby expanding the crown's de jure authority.

In return for recognising the crown's authority under the new Kingdom of Ireland, the Gaelic-Anglo-Irish lords had their position legalised and were entitled to attend the Irish Parliament as equals under the policy of surrender and regrant.

The Reformation in Ireland introduced in stages by the Tudor monarchs did not take hold in most of the country, and did not affect the operation of parliament until after the papal bull Regnans in Excelsis of 1570.

Initially in 1537, the Irish Parliament approved both the Act of Supremacy, acknowledging Henry VIII as head of the Church and the dissolution of the monasteries.

[7] For this reason, and the political fallout after the 1605 Gunpowder plot and the Plantation of Ulster in 1613–15, the constituencies for the Irish House of Commons were changed to give Protestants a majority.

The Plantation of Ulster allowed English and Scottish Protestant candidates in as representatives of the newly formed boroughs in planted areas.

Then, during the reign of James II of England, who had converted to Roman Catholicism, Irish Catholics briefly recovered their pre-eminent position as the crown now favoured their community.

The Jacobite defeat in this war meant that under William III of England Protestants were returned to a favoured position in Irish society while substantial numbers of Catholic nobles and leaders could no longer sit in parliament unless they took a loyalty oath as agreed under the Treaty of Limerick.

For no particular reason, beyond a general pressure for Catholics to conform, they were barred from voting in the election for the first parliament in the reign of George II.

Protestants who did not recognise the state-supported Church were also discriminated against in law, so non-conformists such as Presbyterians, Congregationalists and Quakers also had a subservient status in Parliament; after 1707 they could hold seats, but not public offices.

Much of the old feudal domains of the earlier Hiberno-Norman and Gaelic-Irish magnates had been broken up and given to Irish loyalists soldiers, and English and Scottish Protestant colonial settlers.

Much as in England, Wales, and Scotland, the franchise was always limited to the property owning classes, which favoured the landed gentry.

This in turn severely weakened the economic potential of the whole of Ireland and placed the new and largely Protestant middle-class at a disadvantage.

The result was a slow but continual exodus of Anglo-Irish, Scots-Irish, and Protestant Irish families and communities to the colonies, principally in North America.

In the early 18th century it successfully lobbied for itself to be summoned every two years, as opposed to at the start of each new reign only, and shortly thereafter it declared itself to be in session permanently, mirroring developments in the English Parliament.

Additionally, later ministries moved to change the Navigation Acts that had limited Irish merchants' terms of trade with Britain and its empire.

Furthermore, the Penal Laws meant that Catholics, who constituted the majority of Irish people, were not permitted to sit in, or participate in elections to, the parliament.

The effects of this subordination of Irish Parliamentary power soon became evident, as Ireland slowly stagnated economically and the Protestant population shrank in relative size.

In 1782, following agitation by major parliamentary figures, most notably Henry Grattan, supported by the Patriot movement, the Irish parliament's authority was greatly increased.

The Parliament's records were published from the 1750s and provide a huge wealth of commentary and statistics on the reality of running Ireland at the time.

[14] When William Pitt's idea of union and emancipation was revealed to the cabinet of the Irish parliament, the Speaker and Chancellor of the Exchequer both vehemently opposed it.

[14] An amendment was moved on 22 January 1799, seeking the House to maintain "the undoubted birthright of the people of Ireland to have a free and independent legislature".

[13][14] When parliament reopened on 15 January 1800, high levels of passion ran throughout, and angry speeches were delivered by proponents on both sides.