[Endoperez]

How soon do you start building a second castle? It isn't too hard to conquer two provinces, the second not next to your capital, and have you scout start building a castle in the second one on turn 4, as MA Ulm. If you get lucky, you can have three or four castles by turn 16. Then you can churn out researcher-mages to get on to the magic race.

Read Baalz's guide to Marverni, posted about a week or so ago. It details very nicely what a magic-heavy nation can do in the endgame. Pythium can do that in addition to having strong military; Ulms usually have more trouble.