Both in East and West, the 4th and 5th centuries form the golden age of dogmatic theology, of homiletic preaching, of exposition, of letter-writing, of Church history, of religious poetry.
The art of letter-writing had cultivators in Abbade Costa, Ribeiro Sanches, physician of Catherine II.
For example, since the papal archives were opened, so many regesta have appeared that soon it will be possible to follow the letter-writing of the medieval popes day by day for century after century.
The style has the simple, yet fresh and graphic, directness of all good letter-writing, and there is no lack of passages of keen observation, and even shrewd interpretation.
They are really nothing more than letter-writing services.