Task: Question Answering
Input (English): Passage: Curiously, it appears that the Greeks did not "breed" their slaves, at least during the Classical Era, though the proportion of houseborn slaves appears to have been rather large in Ptolemaic Egypt and in manumission inscriptions at Delphi. Sometimes the cause of this was natural; mines, for instance, were exclusively a male domain. On the other hand, there were many female domestic slaves. The example of African slaves in the American South on the other hand demonstrates that slave populations can multiply.Xenophon advised that male and female slaves should be lodged separately, that "…nor children born and bred by our domestics without our knowledge and consent—no unimportant matter, since, if the act of rearing children tends to make good servants still more loyally disposed, cohabiting but sharpens ingenuity for mischief in the bad." The explanation is perhaps economic; even a skilled slave was cheap, so it may have been cheaper to purchase a slave than to raise one. Additionally, childbirth placed the slave-mother's life at risk, and the baby was not guaranteed to survive to adulthood.Houseborn slaves (oikogeneis) often constituted a privileged class. They were, for example, entrusted to take the children to school; they were "pedagogues" in the first sense of the term. Some of them were the offspring of the master of the house, but in most cities, notably Athens, a child inherited the status of its mother. 
Question: What were entrusted to take children to school?
Output (English): oikogeneis.