The textual sources on the topic of food and foodways in the ancient world are certainly abundant, and in many senses they are also rich and varied. Roman satire touches upon many topics related to food: J. Wilkins distinguishes nostalgia, rural purity, gluttony, hierarchies, and ideas about the elite. Food – which food was eaten as well as how it was eaten – was a prime way of distinguishing between various groups and classes in a society. Diet was an important aspect of ancient medicine because food could bring balance to, or disturb, the humors. Other foods served as drugs. Galen – the second-century doctor and philosopher – addressed food in a number of different ways and in different contexts in the course of his vast intellectual output, among others in his On the Powers of Food. When he had considered his financial situation, Seneca adds, Apicius committed suicide by means of actual poison.