It was originally the custom to burn the whole animal, with skin and hair, but though this extravagant mode of sacrificing was sometimes in use in later times, it became common to burn only the thigh bones and certain flesh parts of the animal, and to use the rest for a festive banquet. In consequence the number of victims was often calculated according to the number of persons invited to the banquet; in other cases it depended on the importance of the occasion, or the fortune of the sacrificers, and even in historical times it was not unusual for whole communities or very rich private citizens to offer a hecatomb (a sacrifice of a hundred oxen), or even several, on which occasions the sacrifice only supplied the opportunity for entertaining the people on a magnificent scale. As a rule, the animals sacrificed must be sound and healthy in every respect; but at Sparta, which was often reproached with excessive economy in sacrifices, diseased cattle were sometimes used. There were several other necessary conditions to be observed; thus, the animals must never have been in the service of man; the ox that drew the plough might not be sacrificed. The sex of the victim generally corresponded to that of the deity to whom it was offered. Even the colour was of importance; white animals were usually offered to the gods of light, black to the infernal gods. There do not seem to have been any fixed regulations with regard to age, except that the animals must have attained a certain maturity.