Xenia is the ancient Greek concept of hospitality, the generosity and courtesy shown to those who are far from home and/or associates of the person bestowing guest-friendship. The rituals of hospitality created and expressed a reciprocal relationship between guest and host expressed in both material benefits (such as the giving of gifts to each party) as well as non-material ones (such as protection, shelter, favors, or certain normative rights).
Theoxeny or theoxenia is a theme in Greek mythology in which human beings demonstrate their virtue or piety by extending hospitality to a humble stranger, who turns out to be a disguised deity with the capacity to bestow rewards. These stories caution mortals that any guest should be treated as if potentially a disguised divinity and help establish the idea of xenia as a fundamental Greek custom. The term theoxenia also covered entertaining among the gods themselves, a popular subject in classical art, which was revived at the Renaissance in works depicting a Feast of the Gods.