Unfortunately, there are no such rules and never there in the history of mankind.
Explanation:
The institution of slavery have been abolished a long time ago. Enslaved people were considered humans but commodities that were used for socio-economic purposes. And therefore they were totally dependent on the will of their masters. Their behavior was governed by the wealthy landlords and favors or punishments were depended on the mood of their masters. Although there were laws of how could enslave people brought their freedom but they stayed only on paper.
