Tip: Something pikemen are good for

[al Roumi]

How do you train them? In my French campaign, I have a few to start, but do not seem to be able to train more anywhere on the map.

i think only the most basic governor buildings allow the recuitment of pikemen. It's a kind of forced obsolescence in that progress prevents you from recruiting "out-moded" units.

other than the ai avoiding them, i don't find them to be so useful tactically.

[Daevyll]

I've found it useful to keep one unit in Fortresses. I put them in square formation right on the flag in the center.

This is quite useful, since any infantry coming over the wall 'open' the gate for their cavalry mates, who then capture the center.
Which leaves you with the option of either relocating units to the center which could have been defendng the wall, or trying to shift enemy units within the 1:30 after capturing. I've lost a few battles due to this.

With the pikemen in square formation, enemy cav doesnt stand a chance of capturing the flag, allowing at the very least a lot more time for you to pull men back from the walls to reinforce the centre.

[Slaists]

i think only the most basic governor buildings allow the recuitment of pikemen. It's a kind of forced obsolescence in that progress prevents you from recruiting "out-moded" units.

other than the ai avoiding them, i don't find them to be so useful tactically.

They are alright as melee troops at the beginning of the game while higher level of bayonetts are not available.