Children from rich homes were often fed by other women, the so-called mammals. Soranus of Ephesus in the 2nd century CE. He proposed to hire a woman between 20 and 40 years of age who has two or three children of her own.
Such a woman should be superstitious, neat, conservative, compassionate, balanced and preferably of Greek origin. In addition, she should not drink alcohol as this may lead to poor development.