The name of this custom, in which people walk or dance on live embers, comes from 'anastenazo' (to sigh or groan) and is practiced in northern Greece by Thracian communities and by refugees from eastern Thrace (the portion of the region of Thrace in present day Turkey) who were resettled in villages in eastern Macedonia (in Greece) with the 1923 compulsory exchange of Orthodox and Muslim populations between Greece and Turkey.
It is also practiced in Bulgaria, on the other side of the border, (also part of Thrace, as these national borders, established only after the Balkan Wars and later, after World War II, do not alter the unity of ancient regional cultures.
This ritual is practiced in agricultural communities, and is most certainly related to fertility rites. Animals sacrificed in connection with this ritual must be uncastrated, so that there fertility remains intact, and the slaughter carried out in such a way as to let the blood soak into the earth.
Specific musical instruments are used for performance of this ritual, the lyra and daouli (see Musical Instruments), though in Eastern Thrace the gaida (Thracian bagpipe) was used along with the lyra. The music was an essential part of these fire-walking ceremonies, its intensity driving the participants to dance on the hot coals. The ritual has been the subject of scientific study, as those who dance on the hot embers do not get their feet burned (though there is a story about a tourist, who, doubtful if there were really hot coals under the dancers feet, jumped in, and had his feet badly burned).