Sentence:  [...] I had hoped to serve in parishes where I could stem the advance of the humanistic teachings which had engulfed the Church. I wanted to teach the faith and doctrine of the Anglican Divines [...] After laboring in a parish for seven years, I finally had to concede this premise was no longer feasible in the Episcopal Church. The bishops demanded all parishes use the new Prayer Book and a female minister was sent to be a “<WSD>priestess</WSD>” in the parish where I served. 
Meaning of the word marked with <WSD> tags:  A female Christian priest or minister, typically in a Protestant, Old Catholic, or independent Catholic denomination.