How did slaves in accent greece differ from models of slavery in later societies?

Ancient Greece was a collection of city states all with their own systems of government and traditions and slaves were treated differently in each place and over time. In general, Ancient Athens practiced chattel slavery though generally they did not enslave members of their own community (although, in the pre-Solon period they sold their people into slavery in order to recover debts). Ancient Sparta on the other hand, had something that was closer to what we would call share-cropping in the sense that the slaves, called helots, were kept in their own communities and were attached to the land which they worked to support their masters. The consequence of that is that the Spartans were paranoid about the likelihood of slave insurrection, which governs most of their foreign policy, but also made them behave in particularly cruel ways to their slave population.

2018 means 2018 ce or common era

there have been other eras too including bce, which included way more years.