I am working with native speakers who are correcting my German writing. I wrote:
Der Mann war an diesem Punkt sicher, daß er einen bekannten Anthropologe werden konnte.
And they corrected it to:
Der Mann war an diesem Punkt sicher, daß er ein bekannter Anthropologe werden konnte.
It seems to me that Anthropologe is the object of the clause and therefore the article and adjective should be declined accusatively. But if they are correct I infer that there is a special rule about professions, unqualified they get no article, and qualified with adjectives they get an article and the qualifiers are declined nominatively. Or is this just a reference to the subject and that's why its in the nominative?