Most everyone agrees that for the vast majority of history one of the common characteristics of civilization was slavery. A large percentage - in many cases, most of the population of every city-state, empire, kingdom, commonwealth (and yes republic) throughout history were slaves.
Was slavery abolished over 100 years ago as most schoolbooks claim? I suppose it depends on your definition of slavery. In medieval Europe, the descendants of Roman slaves gained a measure of freedom, including property rights and (some) freedom of movement. It took many hundreds of years for most of humanity, (most in the West anyway), to gain the amount of individual freedom that the early citizens of the United States (except for women, blacks, and native Americans of course) enjoyed.
Recent worldwide events might cause one to wonder whether civilization has reverted back to the norm - slavery for all except for a small number of very wealthy elite, their retainers and henchmen. If you cannot legally work to gain personal wealth, if your property can be destroyed or stolen without any legal recourse, if your freedom of movement is arbitrarily curtailed, if you can be summarily executed without trial by the king's men, you are most assuredly slaves.
A little over 100 years ago Hilaire Belloc, a British writer, predicted that modern nation-states were becoming slave societies again, due to the accumulation of wealth in the hands of a increasingly small number of individuals, and due to the increasing number of restrictions on individual property rights. He had a solution to this but was not very confident that it would be adopted. And he was right.