Each mithraeum had several altars at the further end, underneath the representation of the tauroctony, and also commonly contained considerable numbers of subsidiary altars, both in the main mithraeum chamber and in the ante-chamber or narthex. These altars, which are of the standard Roman pattern, each carry a named dedicatory inscription from a particular initiate, who dedicated the altar to Mithras "in fulfillment of his vow", in gratitude for favours received. Burned residues of animal entrails are commonly found on the main altars indicating regular sacrificial use. However, mithraea do not commonly appear to have been provided with facilities for ritual slaughter of sacrificial animals (a highly specialised function in Roman religion), and it may be presumed that a mithraeum would have made arrangements for this service to be provided for them in co-operation with the professional "victimarius" of the civic cult. Prayers were addressed to the Sun three times a day, and Sunday was especially sacred.