Castellan's Role

What does the Castellan actually do? I'd assumed it was a role to safeguard the city, perhaps marshalling defence troops etc, but I'm really not sure.

What I do know which may be useful to some people is that the Casellan continually earns XP even when not noticably doing anything, so don't forget to level him / her up periodically!

More about heroes here (Using your heroes to the max).

Its unsure what he fully does, but so far I know this:

- Castellan gives bonus to production
The better diplomacy the greater bonus

- Castellan lowers time for Science
The better Intelligence, the fast you will research

Very useful to know, thank you!