The various chapels in the parish which were served by monks or secular chaplains helped the people of Newmains and district to observe the obligations of assisting at Sunday Mass. It also gave them an opportunity of daily Mass. The chaplains of the outlying chapels thus aided the parish priest in his cure of souls. These chaplains often celebrated Mass in the parish church at side altars placed along the walls or at pillars. One of these side altars was founded by the Somervilles in 1386 and dedicated to St Michael. The chaplaincy of St Michael at Cambusnethan, which was maintained by the rents collected from the Somerville lands, was mentioned in the Acts of the Lords of Council in 1495. Members of the gentry acted as Mass servers in those days, and the names of Somerville and of Hamilton appear among those who served as parish clerk of St Aidan's, aiding the priest at the altar and accompanying him through the parish on sick calls.

At the time of the "Reformation," the vicar and chaplains were scattered. The practice of the Faith in Scotland was driven underground by harsh legislation. The last priest of the old church of Cambusnethan was the Rev. John Lindsay. When he offered up the last Mass in the parish church, he knew that the time would come again when the Faith would flourish in the land of St Nethan.