Sacrifice has been seen, in a diversity of societies and historical periods, as a form of communication between the living and the dead, and as a means of sustaining and renewing social life. It is performed as part of rituals which connect the human world with that of the spiritual, and involves the offering of a gift (an animal or a human which is killed) to a more powerful being (for example, a god). As well as playing an important part in biblical texts and classical myths, sacrifice can be understood in relation to human impulses such as violence, and in terms of the maintenance of collective social relationships and identities.