Building forts near bridges

[Es Arkajae]

yes just build an army and just put it on the bridge

And pay the enormous maintenance for it if you're keeping it there. I don't know about you but I build armies to go around conqering stuff, not sit around on their arses near bridges, stealing the locals chickens and harrassing their womenfolk

Forts are excellent for guarding frontiers, just build them, stick them at choke points with a unit of town guards inside and presto!

They prevent an enemy from rushing into your territory and besieging your cities by holding up an enemy army long enough for you to send an army to lift the siege and deal with them.

This keeps enemies off your land.

They also act as watchtowers of a sort and help to discourage the formation of bandits in the area.

As for the thread question it depends, if the other side of the bridge is someone elses territory (someone I'm not at war with) then putting a fort there would be a trangression. Otherwise yes I prefer to place them on the far side as it allows me to just stick my relieving army on the bridge where the enemy can still reach them, thus forcing the enemy into a bridge battle where I'm the defender.

Though there is one annoying bridge on the map, between Thrace and Tribus Getae where you can't stick a fort on the southside of the bridge despite it being perfectly flat/non-swampy, oh well.

[The Stranger]

i'm not telling on every bridge just the main bridges with gaul i hold of the romans for 50 years with one main army

[Paul Peru]

Depends...
A) If you are expecting action, put your army on the bridge, as previous posters suggest. You may want to have a fort on your side of the bridge as a backup, though. If defeated the army on the bridge will retreat there, and the enemy will have to siege.

Not expecting action:
B) If the other side of the bridge is neutral or allied, put the fort on your side to avoid transgressing.
C) If the other side is enemy, protectorate or you have military access (never happened to me) you may consider putting the fort on the other side to see a bit further, but putting it on you own side lets you fall back to A) or B) when necessary and lowers the risk of brigands.

Either way, man the fort with something with low upkeep. I use depleted mercenary units.