Hi,
If you make a lance charge against a foe and end the round with another enemy in your
your sights, can you make another lance charge against this new foe or do you have to continue
in a straight line for the second round? It would seem the momentum of the horse would be spent
after the first lance charge.

I'd say it depends how close together they are. In various literature sources, knights do make several lance attacks in a row, so it would be within the genre. I think Erec in Erec et Enide takes on several knights at once dismounting all in turn.

NT

Hi,
If you make a lance charge against a foe and end the round with another enemy in your
your sights, can you make another lance charge against this new foe or do you have to continue
in a straight line for the second round? It would seem the momentum of the horse would be spent
after the first lance charge.

I'd rule that you will have to continue more or less in a straight line (like Eothar said in his answer), or slow down, turn the horse and then accelerate to a charge again. The momentum of the horses is NOT spent when lances clash; no human grip would be enough to hold onto the lance to allow that much momentum to be transferred. Now, in stories, you occasionally have jousters bringing down man and horse, but I'd interpret that as the other horse stumbling at the strike. If the enemy knights are obligingly in a 'line' formation (in order to get their own lance charges in), then as long as you have your lance intact, you will be able to lance charge against them, too.

Now, in stories, you occasionally have jousters bringing down man and horse

Might be possible in later periods with lance rests and war saddles. You might also cause the horse to "fall" backwards if the dismounted knight never lets go of the reins and effectively pulls the horses head around. Horses, like most cephalate animals, follow their head.

Nevertheless, I think answer also comes down to, "what do you want to happen?" Set them up in a line, let the PK unhorse all of them, or spread them out and let him only charge one.

Certainly fun if he can dismount all of them.

NT

Might be possible in later periods with lance rests and war saddles. You might also cause the horse to "fall" backwards if the dismounted knight never lets go of the reins and effectively pulls the horses head around. Horses, like most cephalate animals, follow their head.

Good point; that actually seems like the more probable outcome, the reins being yanked rather than direct impact of the lance.

I have seen medieval jousting rules stating that, if both knights are unhorsed, and one falls with his horse and the other without, the former knight wins, because his fall is alleged to be his horse's fault and not his own. I think that that implies that horses had a certain tendency to stumble or some such.

That said, I feel like, in literature, when a knight jousts down a knight and his horse, it is typically implied to be a result of his puissance, rather than a lesser result than simply unhorsing the knight. So it seems likely that there could be multiple causes.

I have understood the knight and horse going down together indicates a mighty blow, not stumbling
And I am currently reading Perceforest where, several times, knights are unhorsed when their saddle straps break, and leave them sitting on the saddle on the ground; Though they are always ashamed for their performance bystanders always insist that they were not actually knocked off, and it's the saddle's fault
Finally, in Malory several times when a knight is unhorsed or knocked down the knight jumps up and says, "My sword will not fail me where the son of a mare has!"
So I think it is the GM call
Or maybe the call of the judges of the Tournament