In Classical Athens everybody except the really poor had slaves. Slaves who belonged to an oikos and stayed permanently in the house were called oiketai or oikeis. These 'house slaves' were used both for domestic chores and for land work. Their duties included looking after children - this was done by the trophos or the paidagogos - and escorting the women of the family to religious festivals and the men on their hunting trips.

At Athens there was a special ceremony for integrating a slave into the oikos. All the members of the family led the slave to the hearth of the house, where the mistress of the house showered him/her with nuts, figs and sweetmeats, and the slave was named.

The slave would be attached to the house for the rest of his/her life, and some slaves would actually have been born in the house. This encouraged feelings of devotion towards 'the master'. Moreover, their destinies lay in the hands of those they served.

This special relationship meant that house slaves had more hope of obtaining freedom than other kinds of slave. By the end of the Classical period, the will of the kyrios usually included a clause granting freedom to some slave or other in recognition of his fidelity. 'Freedmen' - as freed slaves were called - were at liberty to go back to their homelands. But if a freedman stayed on in Athens, he could go on the city register as a metic, and his ex-master would undertake to become his protector.