All castles in Heroes 3.

As I noticed, there are different people gathered here! Including those who call themselves Grandmasters, Experienced Players, and Newbies (which is very pleasing to me)...
...So, I'll tell everyone that many first-month development tactics have been tested... you won't believe it... the tactic that involves building the Capitol first proved to be the most effective, but there's a caveat: this only applies if you're not playing as Sylvan.