What Killed Roman Slavery

I remember reading somewhere that on Basil II's campaigns he managed to bring in tens of thousands of POWs as slaves. In turn however the later campaigns under the Komnenoi and later don't say much about that sort of warfare.

What happened between the time of Basil II and Alexios that killed the sort of widespread slavery that the classical empire was known for?
 
Shifting economics, when long-range trade broke down you no longer needed specialized slave production but rather generalized serfs in your local area. The serf offered levees and unlike the slave did not need to be policed. No point for hundreds of slave potters when you can't sell to an empire of 20 million across the Mediterranean.
 
Top