This was the case of Telemachos receiving in Pylos. After he had exposed his intensions and the goals of his trip, Nestor offered him his advice and material support as a manifestation of the friendship and reciprocal aid the leaders of different Greek cities often used to give each other as a result of reciprocity. From an unwritten law, xenia progressed into becoming an institution, like, for example, in the city of Eretria that: "could pass a decree saying that a named citizen of the city-state of Taras should be proxenos for all the citizens of Eretria who found themselves in Taras" (Hansen,127). Hansen further explains that the institution was comparable to the modern institution of a consulate.

The propriety of guest friendship was further asking Nestor, in his leadership position and as a head of the house, to offer his guests not only food, drink, advice and support on their journey, but also a shelter until they left. As he exclaims when they intend to return to their ships for the night: "heaven and the immortal gods" (Odyssey, III) are requesting him to oppose such a profanity and offer them beds in his own house. The laws of hospitality were thus expressed not only as arrangements between human beings, but as commands of a higher authority, the gods. Not abiding by these laws it would not only mean a breech of an unwritten contract, but also a profanity....

It appears to be the same as if one would disregard the proper ritual of morning and burial ritual. The manifestation of xenia goes as far as Nestor offering Telemachos one of the highest signs of respect: he offers his own daughter, Polykaste, to bathe and then dress Telemachos. The effects of xenia are thus more evident, since the representative of the leadership of a city is offering his daughter to the possible leader of an allied city, resembling the alliances between the royal courts in the western world. All along, the mission Telemachos is on is accompanied by the blessing of the gods, by the presence of Athene along his side. She is even showing herself to his allies when she finds it necessary to point out that he is protected by the gods.
All in all, the propriety of guest friendship was not only a custom of the Greek cities during the Helenic and classical periods, but it was a law imposed by very considerations of existence. The civilized world was characterized by trading, immigration, alliances and they were possible only under the circumstances of xenia.

Works Cited:

Hansen, M.H. Polis: an introduction to the ancient Greek city-state. Oxford University Press, 2006

Gill, C.Postlethwaite, N. Seaford, R. Reciprocity in Ancient Greece. Oxford University Press, 1998

Homer, tr. By Lattimore, R. Odyssey