The Society for the Irish Church Missions (ICM) was founded in March 1849, through the work of an English clergyman, Reverend Alexander Dallas. With the help of Miss Fanny Bellingham in Dublin, Dallas was able to send literature and recruit eight Protestant Gospel preachers in October that year to preach. Following his own successful preaching ministry in the west of Ireland in 1847, Dallas received the support of the Bishop of Tuam, Thomas Plunkett, to ordain a clergyman to work on behalf of ICM in Castlekerke, County Galway. In March 1849, The Society for the Irish Church Missions to the Roman Catholics was founded and received the support of over 200 Irish Clergy who signed a resolution of support at the annual gathering of the missionary societies in April 1849.
Source: https://www.irishchurchmissions.ie/new-blog/2019/3/20/origins