I recently purchased the game, and though my first campaign is a writeoff, an interesting problem arose.

By using a slow expansion strategy combined with trade, I eventually found that myself and my major trading partner (egypt) were the only two factions with any coastal presence. The situation was complicated by the fact that they controlled many more provinces (including all of the ones that could turn a good profit without trade). As soon as war breaks out, I go from making 15k florins/turn, down to losing several thousand.

As far as I have been able to ascertain, there is only one viable way to counter this (while still keeping a trade based economy). If you crush turkey early on then you effectively drive a wedge between europe and the holy lands (the same goes for taking morocco). By splitting up the world into separate chunks like that, you make it much more difficult for any one faction to dominate the map (and thus ensure a reasonable chance of maintaining economic domination).

The other possibility I thought of would be to harde vast amounts of gold until as late as possible while improfing your economic infrastructure with mines and farming.

Any other ideas?

Is there another way?