On completing their studies, candidates were formerly "licensed to preach" by their home presbytery and became a probationer, serving a 12 or 18 month full-time probationary period in a parish. This probationary year has now been replaced by a final 15 month placement, although the objective remains very similar (albeit with more short residential training courses.) When the training has been sustained, the candidate is free to seek a charge. The Church of Scotland does not ordain ministers without simultaneously inducting them into their first charge. This is because, theologically, ministers are ordained "to do" a task rather than "to be" a minister. This stands in contrast to some other denominations which ordain their clergy on completion of training. Theological colleges Prior to Church union in 1929, the United Free Church of Scotland maintained its own colleges in Edinburgh, Aberdeen and Glasgow, whilst candidates for the ministry in the Church of Scotland studied in the University Faculties of Divinity. The union of 1929 necessitated the integration of the two systems. The theological colleges now form integral academic schools at the universities of St Andrews, Glasgow, Aberdeen and Edinburgh. The Church used to appoint the Professors of Divinity along with certain other chairs but the cost of maintaining these chairs necessitated transferring patronage to the academic senate or university court of each university. Though technically still Church colleges, these are almost indistinguishable from the university schools. The Church still advises on the appointment of professors and advises on the appointment of the principal of the college. The head of the School of Divinity at St Andrews is currently (2015) Mark Elliot. The principal of St Mary's College is Ian Bradley and as he is an ordained Church of Scotland minister, he is entitled to use the prenominal Very Reverend whilst in office. Role of the elder A ruling elder is ordained by the minister and Kirk Session of the parish, and is answerable to the Kirk Session. Like a minister, an elder is ordained for life. Unlike members of parish councils in other denominations, elders are understood to have pastoral responsibilities, which they carry out under the guidance of the minister. Usually a parish will be divided into elders' districts, and the elders are expected to visit the church members resident in their district on a regular basis. Elders also often assist the minister in the distribution of the elements at