Around 1833 the Church of Scotland entered an ear of intense controversy called the "Ten Year Conflict."
It culminated in the Disruption which Donnachie (2001) says was one of the major events in Scotland in the 19th century.
In essence it was about the age old opposition to patronage! Congregations should be allowed to choose their own ministers whatever the views of patrons. Aristocratic privilege should be resisted! (Devine 1999).
Matters came to a head at the General Assembly of 1843 when Thomas Chalmers (1780-1847) and 470 Ministers from the more conservative evangelical wing seceded from the established church. This was over a third of the clergy. They also took about 40% of the laity.
And it led to the establishment of a new church, the Free Church of Scotland!