Every year, the cities are expected to pay the Dragon's Levy, 1000 slaves are sent out in the desert from each of the seven cities.
Only once has a city (Balic, millennia ago) failed to pay the levy, gathering only 900 sacrifices.
The Dragon then came to Balic, destroyed a quarter of the city and took away 100 templars to fill its "quota". Since then, no city has failed to achieve the quota. However, Tyr looks like it won't make it this year.
Daskinor of Eldaarich, did have a run in with the Dragon many ages before Andropinis, I believe it was levy related as well.
He was always something of a loner, that Daskinor, but after that incident, you could be tempted to consider the King quite strange, if not actually totally mad. Well let's not ponder on the Dim lands, they are all but forgotten.
Spoiler don't read, if you are not a DM..
As far as I remember, the Dragon used part of the levy to keep Rajaat the warbringer sealed in the Hollow.
You could say, do a bad thing to stop a bad thing.
Dungeon issue 80: Eye on Dark Sun: Dragon's Altar by Rodney Thompson
(Sheds light on the subject of how, and where)