While in the De regimine Giles carefully avoids any reference to the thorny problem of the relationship between secular and ecclesiastical power, his later writings which are relevant for political theory deal first and foremost with ecclesiological problems.
In the preparation of a standard Latin version, the biblical scholar Jerome (c. 347 419/420) separated "canonical books" from "ecclesiastical books" (i.e., the Apocryphal writings), which he regarded as good for spiritual edification but not authoritative Scripture.
Here also belong, very definitely outside the ecclesiastical and royal pale, the body of writings, doctrinal and apocryphal, of the Bulgarian Bogomil heresy, provoking from official quarters those lively and informative reactions of Presbyter Kozma and of Tsar Boril's synodal convocation of 1211.
The church's selection of canonical writings presupposes a dogmatic distinction between "ecclesiastical" teachings which, in the opinion of its responsible leaders, are "apostolic"—and "heretical" teachings.
After the condemnation in 554 by Pope Vigilius of the Three Chapters (heretical writings based on the emperor Justinian's ecclesiastical policies), Aquileia seceded from Rome, its bishop Macedonius adopting the title of patriarch in defiance of the Pope.
The treatises "On the Divine Names," "On Mystical Theology," "On the Celestial Hierarchy," and "On the Ecclesiastical Hierarchy" comprise the bulk of the Dionysian corpus of writings, supplemented with 10 letters affecting a 1st-century primitive Christian atmosphere.
As an editor and expositor of classical texts and the writings of the Church Fathers, as a commentator on the ecclesiastical conflicts of his time, and as a scholar, wit, and satirist, he was unsurpassed by any humanist in northern Europe.
This was the task that he undertook in most of his extant writings, and the more systematic theology is founded on the ecclesiastical doctrines of the Trinity, the incarnation, salvation after death and the inerrancy of scripture.
He has been described as the "patron saint" of American evangelicalism and his writings have found a new generation of readers in a world where many Christians are disenchanted with the failings of clergy or ecclesiastical institutions.
