During the period in which the Unitas Fratrum dissolved in exile, Comenius felt the Anglican church to be the most competent to contribute to the reconciliation of the churches, and thus to world peace. To contribute to the realisation of this aim, Comenius wished to transmit the best ideals of the Brethren, their “rare estate”, and by doing so have these adopted by their successors. Comenius published this collection as an introduction to the history and the organisation of the Brethren. In this, he was acceding to the wish of English friends dissatisfied with the discipline in their own church; they wished to learn about the structure of the Unitas Fratrum and use this information to better themselves. The volume comprises three parts (see the separate entries for the Ecclesiae historiola, the Ratio disciplinae and the Paraenesis ad ecclesias).
For further study, see also:
Jan Kumpera, J. A. Komenský, poutník na rozhraní věků. Prague & Ostrava 1992, pp216-217