Three things

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The ancillary Henry got was a pagan magician. Let's hope he doesn't meet an inquisitor again or it will get hot


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Otto is still in charge of the crusading army. Possibly due to a bug as Henry had less command when he joined Otto. Rejoining Henry to the stack leads to Henry taking over btw.


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Jobst should not wait for Ulrich. Sally forth. I just did it as a test and beat back the French. The way to do it is to put all your missiles on the wall. (except for 2 PAs)
T PA PXB T T CB CB T CB
where T are towers.
Everyone else stays on the bottom inside.
Once battle starts, move your 2 unupgraded PAs out the gate so they stand just in front of it in a thin line, tight formation.
Have them on fire at will and not on skirmish.
What you will notice is the AI sends all its ranged units forward to shoot them. They will be picked off by your towers and your missiles on the towers as well as the two units on the ground. You will lose both units on the ground eventually (actually you'll have 8 men left in each) but it will lead to the AI losing ALL of its missile units (well again, 2-9 men per unit left)
During that procedure, the AI won't utilize its ballista btw.
You can then choose to charge in and drive them from Dijon with mediocre casualties or you can wait a turn, take a few starvation casualties and then at the next sally move all missile units out the gate in a thin line and shoot his cav (he doesn't have missiles to counter you and will be passive) His ballista will likely retaliate then but since your units are in thin lines (max 3 deep), it will not do much damage.
Once his knights are gone, shoot the spears. Then use cav to line up outside and charge him.
Chances are though that the French will withdraw after your first sally when you take out all his missile.
Gotta love passive (or non passive but stupid) sally AI