From Cromwell to the Boyne
Cromwellian Ireland had no parliament of its own, but was merged into one Commonwealth with England and Scotland, sending six - later 30 -members to a single Parliament at Westminster.
From 1653, Cromwell ruled more directly as Lord Protector of England, Scotland and Ireland.
After long negotiations, Parliament passed an Act of Settlement in August 1652, confiscating the majority of Catholic-owned land and granting it to English and Scottish settlers. It also banned Catholics from either voting for, or sitting in, Parliament.
Protestant ascendancy
This Cromwellian settlement proved difficult to administer, although its importance to the later history of Ireland was immense. It shifted the balance decisively towards Protestants in both land ownership and civic life, a Protestant Ascendency that lasted until the late 19th century.
Irish members continued to sit in the Commonwealth Parliaments of 1654, 1656 and 1659 but these played no great role in Irish affairs, and only in 1659 did the Irish members exert any real influence.
With the restoration of the Stuart monarchy and King Charles II in 1660, the Commonwealth was abolished and the Irish Parliament reconvened the following year.
Tariffs
There was occasional tension between the English and Irish parliaments. Beginning in the 1660s the English Parliament passed Navigation Acts which placed tariffs on Irish products entering England, but exempted English goods entering Ireland.
Ireland then became the main battleground following the Glorious Revolution of 1688, when the English Parliament replaced the Catholic King James II with the Protestant King William III, Prince of Orange.
The hastily-convened Irish Parliament of 1689, which was very largely Catholic in membership, supported James, hoping to reverse Cromwell's land confiscations. However, at the Battle of the Boyne in 1690 William's forces outnumbered and defeated James's.