The job of the Preacher, as the name implies, was to preach a sermon on Sunday morning during term, and the post was invariably given to well-known clerics.
The remaining duties of the Chapel continued to be carried out by the Chapel Readers (or Chaplains, as they were known up to the Reformation), a post established in 1315. Sometimes an Afternoon Preacher was also appointed, if the Chapel Reader of the day refused to give the afternoon sermon on top of his other duties, and on other occasions an Assistant Clergyman.
In 1919, when the Preachership fell vacant, Pension decided that the Chapel no longer required two clergymen, and made no appointment; the then Chapel Reader, the Revd John Phillips, assumed the Preacher's duties. He resigned however in the following year, when the Revd Walter Matthews was appointed Chaplain, a post formally amalgamating both previous posts, to which in 1928 the title of Preacher was given.
View the names of the Inn's Preachers (PDF)
This document gives the list of Preachers from 1574, when the post was established.