It is certain that Hilary was busily engaged in writing his great work upon the Trinity, and that some parts of it were actually published, during his exile. But as this work in its final form would appear to belong to the next stage of Hilary’s life, it will be well to postpone its consideration for the present, and proceed at once to his share in the conciliar action of the time. We have no information concerning his conduct before the year 358, but it is necessary to say something about the important events which preceded his publication of the De Synodis and his participation in the Council of Seleucia.