Mounted Combat

We hadn't dealt with using weapons and spells from horseback thus far in the campaign, and I was ill-prepared to adjudicate this during the skirmish with the wargs. The 2e DMG discusses mounted combat in detail; below are some of the key points. From p. 76:

Mounts trained for combat (a heavy warhorse, for example) present few problems. These can be used in mounted combat with no penalties. However, steeds not trained for combat are easily frightened by the noise and confusion.

Those fighting from the back of untrained creatures suffer a -2 on their chance to hit, since much of their time is spent simply trying to keep the mount under control.

The horses purchased in Luskan are riding horses only, so going forward this -2 penalty will apply. With regards to melee combat:

In mounted fighting, a character gets a +1 bonus to his chance to hit creatures smaller than his mount. Thus, a man on horseback gains a +1 bonus to his attack rolls against all medium-sized creatures such as other men, but would not gain this bonus against another rider or a giant. Those on foot who fight against a mounted rider, have a -1 penalty; this not applied to attacks against the mount, however.

This would have reduced the first penalty to -1, since the wargs were medium-sized creatures. The wargs wouldn't have incurred a penalty, since they were attacking mounts or dismounted PCs. Missile combat, understandably, is more difficult:

Missile fire from the back of a moving horse is possible only if the rider is proficient in horsemanship. Even then, only short bows, composite short bows, and light crossbows can be fired from horseback by normally proficient characters.

Long bows can be used by those with specialization (if this is used). Heavy crossbows can be fired once, but cannot be reloaded by a mounted man since the bracing and pull is inadequate.

There are details beyond this, including penalties if trying to fire while the mount is moving, but let's leave it here until that situation arises. We don't use proficiencies, but I'll allow short bows and light crossbows to be fired by PCs succeeding a Dexterity check, with failure meaning that the round is lost trying to control the mount (with no ammunition expended). Spellcasting can work similarly. Fair?

I also was too liberal in causing characters to fall from their horses in combat, some of which I corrected during the session. Even Aranos' fall, however, shouldn't have happened, by the book. Here are the relevant excerpts:

Killing the Mount: This is the grim and efficient method. Once the horse (often an easier target) is dead, the rider is certainly dismounted. The steed automatically falls to the ground.

If the rider has the Riding proficiency, he can attempt to land safely on his feet on a successful check. Otherwise, the character also falls to the ground and suffers 1d3 points of damage. The character cannot take any action that round and must spend another entire round gathering himself back up and getting to his feet.

Again in the absence of proficiencies, a Dexterity check should suffice to avoid taking damage from a fall. Aside from killing the steed, an attack roll of 20 will dismount a rider, but a "normal" hit against either party will not:

Weapon Impact: Riders also can be knocked off by solid blows from a variety of weapons. Any time a rider hits another mounted character or creature with a melee weapon 3' or longer and scores a natural 20 on the roll, the other character is knocked from the saddle, suffering 1d3 points of damage (if from the back of a normal horse).

There's a lot here to digest, and more in the actual rulebook. I turned out to be a bit harsh in my rulings, but should be better equipped to deal with this next time.