Despite periods of persecution, Presbyterians began to form congregations and build their own churches, and by the end of the seventeenth century an overarching ruling body known as the General Synod or Synod of Ulster was established.
For many members of the establishment, Presbyterians were regarded as
more of a threat than Catholics, especially because of their numerical
superiority over Anglicans in much of Ulster. Certain restrictions were
placed on Presbyterians as a result of the Penal Laws passed in the
Irish parliament. Even after the passing of the Toleration Act in 1719,
under which Presbyterians were granted freedom of worship, there was a
strong sense of estrangement from the Anglican and landed establishment,
and this was a contributory factor in the large-scale emigration of
Presbyterians from Ulster to America in the eighteenth century.
In 1840, the General Assembly of the Presbyterian Church in Ireland was formed by the union of the Synod of Ulster and the Secession Synod.
Today the Presbyterian Church is the largest Protestant denomination in
Northern Ireland with over 500 congregations, overwhelmingly in
Northern Ireland, but with a significant number of congregations in
other parts of the island, especially counties Donegal and Monaghan as
well as the city and environs of Dublin.