The former president of Coláiste Mhuire, Marino, Dublin, has described how she was "humiliated, punished, isolated and excluded" at the college, which is run by the Christian Brothers.
In a letter to a senior figure in the Christian Brothers, Caoimhe Máirtín says many of her colleagues were also "intimidated, harassed and bullied."
She writes: "I have seen many colleagues, men and women of all ages, crying, frightened, intimidated and bullied. I have seen brothers crying, upset and broken."
The letter, obtained by The Irish Times, shows that the Christian Brothers were alerted to intimidation and bullying at the college in September of last year.
She writes: "What is most frightening for me is that both brothers and former lay employees have indicated to me that my experience is not unique - that an oppressive and unhealthy culture had existed for some time prior to my arrival in 2000 and that many people have left under pressure."
Her letter was sent to Br Mark McDonnell, a trustee in Ireland of the Christian Brothers before his departure to Rome some years ago. The letter was circulated among the leadership of the brothers and among key personnel in Coláiste Mhuire.
Last week, Ms Máirtín resigned her post after claiming in a High Court action that she was subject to bullying, intimidation and psychological abuse by the trustees and governing body of the primary teacher training college. The case was settled out of court last week.
In her letter she says she was "used and abused in Marino. . . I have raised the issue of an inappropriate work environment both verbally and in writing in Marino at management level, at governance level, and at trustee level. Nobody appeared to care, to listen or to check out the truth of my comments."
Draft audited accounts for the Marino Institute of Education, which controls Coláiste Mhuire, show a surplus of more than €2m over the past three years. Despite this, the INTO said last night that staff at the teacher training college had often been denied adequate resources.
Ms Máirtín writes that her "greatest fear" is that the Department of Education will now use this opportunity to close Coláiste Mhuire and allow Froebel College and the Church of Ireland College in Rathmines to form an interdenominational college on the Rathmines' campus."
Ms Máirtín is a hugely respected figure in education circles. Regarded as a progressive and strong leader, she is widely credited with the transformation of Marino into one of the State's leading teacher training colleges.
Sources in the Christian Brothers say she ran into conflict with the management of the privately run college after she began to question the allocation of the €4.5 million paid by the State to the college every year. Ms Máirtín also writes in her three-page letter about support for her position from some Christian Brothers.
Ms Máirtín was unavailable for comment last night.