Occasion. The eighth disputation of the fourth Leiden cycle, defended 30 March 1605 under Arminius by Andreas Knutius of Wesel. It follows directly on the disputation De creatione mundi and opens the treatment of the world's rational inhabitants, angels before men.
Authorship. By the convention of the Leiden faculty the theses are the presiding professor's; the student defended them. Stanglin argues the case for Arminius's authorship of the disputations at length, and it is his argument, not ours.
The doctrinal move. Arminius builds the whole doctrine out of a single definition — angels are spirits subsisting in themselves, finite, rational, immortal, created to praise God and serve him in the government of the world — and then unfolds it term by term, so that every later claim is answerable to the definition rather than to authority or speculation. The polemical edge is directed twice: against those who reduce angels to good or bad motions of the soul, and against the scholastic hierarchies, which he sets aside in a sentence.
Where it is answered. Nowhere directly; the topic was not contested between him and Gomarus. Its interest is methodological — it shows Arminius doing ordinary Reformed scholastic work on an uncontroversial locus, which is precisely the context the polemical disputations lack.