Serfs often had fewer rights than Roman slaves. Sure, they often couldn't be sold and moved around, but they also had no way of winning their freedom, their chi

Serfs often had fewer rights than Roman slaves. Sure, they often couldn't be sold and moved around, but they also had no way of winning their freedom, their children were automatically slaves as well, there were no legal repercussions of any kind for lords that treated their serfs badly, there were no legal obligations to leave any kind of food for serfs etc. Roman slaves were protected by national laws to a much, much higher extent. Additionally, feuds between neighboring lords, which were extremely commonplace in much of Medieval Europe, often involved deliberate attacks on serfs, with the sole purpose of killing them off. This was also mostly unheard of in Rome, and would have led to legal punishments against the slave killers if it could be proven. Of course, this started gradually changing, and the exact conditions for serfs varied greatly between regions. But by-and-large, Medieval Europe was much worse off then many areas of the Roman Empire. And in regards to efficiency, this all makes no sense. The Roman Empire was vastly more economically efficient than medieval Europe, particularly when it came to food production. The kinds of armies the Roman Empire could field (which is mostly limited by feeding them) were not seen again in Europe until near the modern era. The Roman Army ranged from ~300,000 soldiers in the time of Tiberius, to more than 600,000 in the time of Constantine. By comparison, with the exception of Charlemagne (who still raised at most 100,000 troops once, and could hardly sustain this), medieval Europe had tiny armies - William the Conqieror conquered England with 14,000 troops, for one example of the scale.