Conversation so far:
What is Trinitarian theology?
In The Triune God: Doctrines, Lonergan begins with an examination of the dialectical process by which the dogma of the Trinity developed in the first four centuries.
Did he believe this?
CANNOTANSWER.
Did he believe in a certain theory?
CANNOTANSWER.
Did he study this theory?
Lonergan develops the theory of intelligible (or spiritual) emanations in God as propounded by Thomas Aquinas.

Question: What is that about?
Self-contained rewrite: What is the theory about?