The intention of this work is to provide a sketch of the History of the Church in the first six centuries of its existence, resting throughout on original authorities, and also giving references to the principal modern works which have dealt specially with its several portions. It is hoped that it may be found to supply a convenient summary for those who can give but little time to the study, and also to serve as a guide for those who desire to make themselves acquainted with the principal documents from which the History is drawn.