Actually, I'm not really sure. But you mentioned posioned lances for killnig dragons. She wrote a book a long time back titled, appropriately enouhg, Dragonsbane in which a courtier travels to find the only living dragonsbane in the kingdom. When he finds the guy, he is shocked and dissapointed to find that the way he killed the dragon was sneaking up on it and killing it with a bunch of poisoned harpoons. It was a good book, especially for being written in the 80's.
Gabriel