The 19th century was a century of turbulence for religion in Scotland. The Established Presbyterian Church in Scotland was split by the Disruption of 1843 in which the inbuilt tensions between the claims of religion and the claims of the state came sharply to a head.
Industrialisation had produced a powerful new manufacturing class that was to become active in politics both in Edinburgh and in London and was to take a new interest in religion. At the same time there was a series of Evangelical revivals within the church. A new party, the Evangelicals, had a majority in the General Assembly of the Church of Scotland from around 1834.
The Reform Act of 1832 raised issues about at least limited democratic participation in government. What did this mean for the Church? The tradition had been for new ministers to be presented to parishes by a patron, sometimes from the old landed classes, but often by the Crown. Two Acts of the General Assembly of the Church in 1834, the Chapels Act and the Veto Act, challenged the status quo. Parishes would now have a right to refuse ministers they did not want. The Courts ruled the Church's actions illegal. In May 1843 a third of the ministers and almost half the members walked out of the Assembly to form the new Free Church of Scotland. Now there were two parallel Presbyterian churches, one stressing the freedom of the Church, the other supporting continuing responsibility for the whole community. There were large gains and large losses.
One of the leaders of the Free Church was Thomas Chalmers who had been minister of the Tron Church (1815-1820) and then of St John's (1820-1823). The Free Church and the Church of Scotland re-united in 1929 and the main reminder of the Disruption is the Free Church, Trinity College in Lynedoch Street.