Complex sentence: Besides slaves, people of certain professions were also in the cheonmin class, for example professionals dealing with animal slaughter (butchers, people working with animal skins), most probably because of old Buddhist views.
Split into simpler sentences: Besides slaves, people of certain professions were also numbered among the cheonmin class. For example professionals dealing with animal slaughter (butchers, people working with animal skins), most probably because of old Buddhist views.