Mischief
It's mostly the king's soldiers that were after the dragons. Why: because the King wanted to know The Secret.So he sent out his soldiers to catch one of the dragons for questioning.
Catching a dragon was not easy in those days. There are many reasons for that. Dragons are incredibly strong and surprisingly quick, most could still throw flames, they are good at disguise, they are very good in sword fighting and, they got dragon magic. One just has a hard time staying mischievous when one is very close to a real dragon.





Obviously some battles were inevitable