Eranos was essentially concerned with *reciprocity: at first of food, and later of money. In *Homer, eranos refers to a meal for which each diner contributed a share (Od. 1. 226); alternatively, the venue might be rotated. This earlier meaning was never lost (Xen. Mem. 3. 14. 1); but, by the later 5th cent. bce, the concept had evolved to include a *credit system, common in Athens, whereby contributors lent small sums to help out a common acquaintance in need (Lys. 20. 12; cf. Pl. Ap. 38b). The strong obligation to lend was matched by a reciprocal obligation to repay as soon as possible. The reciprocity inherent in the eranos-idea is reflected in metaphorical usage: to die in battle for the polis was to offer one's kallistos eranos (‘finest contribution’), receiving in return ‘immortal praise’ (Thuc. 2. 43. 1). Readiness to contribute towards eranos loans could be cited in Athenian courts as an aspect of civic virtue (Antiphon 2. 2. 12); failure to repay as indicative of general degradation (Lys. fr. 1 Carey). Disputed is the extent to which eranists in Athens were ad hoc groupings, or fixed associations (see clubs, greek), somewhat resembling friendly societies.