]. TEMPORAL CLAUSES DENOTING PURPOSE
Temporal conjunctions denoting limit as to duration (so long as, while) or limit as to termination (until, till) may imply purpose.
a. So ἕως till, against the time when, in order that, πρίν before, in order that not. ὄφρα (poet.) is usually final (in order that) rather than temporal (so long as, while, till, up to the time that). Sometimes in post-Homeric Greek ἕως and the subjunctive (with or without ἄν) has a touch of purpose.
In the Odyssey ἕως, usually with the aorist optative after a secondary tense, is almost a final conjunction. Thus, δῶκεν . . . ἔλαιον εἵως χυτλώσαιτο she gave olive oil that (against the time when) she might anoint herself ζ 79. So δ 799, ε 385, τ 367. In ι 375 the present optative expresses durative action (θερμαίνοιτο gradually get hot).
After a secondary tense ἕως with the aorist optative sometimes in Attic prose implies an expectation, hope, or purpose on the part of the subject of the main verb that the action of the temporal clause may be attained. Since such optatives are due to the principle of indirect discourse, the subjunctive with ἄν, denoting mere futurity, might have been used instead.
σπονδὰ_ς ἐποιήσαντο ἕως ἀπαγγελθείη τὰ λεχθέντα they made a truce (which they hoped would last) until the terms should be announced X. H. 3.2.20 (here we might have had ἕως ἂν ἀπαγγελθῇ), τὰ ἄλλα χωρία εἶχον μένοντες ἕως σφίσι κἀ_κεῖνοι ποιήσειαν ( = ἂν ποιήσωσι) τὰ εἰρημένα they retained the other places, waiting until they (the Lacedaemonians) on their part should have performed for them (the Athenians) what had been agreed on T. 5.35. Compare ἕως ἂν ταῦτα διαπρά_ξωνται φυλακὴν . . . κατέλιπε he left a garrison (to remain there) until they should settle these matters X. H. 5.3.25 (here ἕως διαπρά_ξαιντο might have been used). Other examples are L. 13.25, Is. 1.10, 7. 8 (ἕως οὗ?), X. H. 4.4.9, D. 27.5, 29. 43 (τέως), 33. 8; cp. also Ar. Eq. 133. Present optative in T. 3.102, X. H. 5.4.37.
ἕως ἄν with the optative occurs rarely where it might be thought that the simple optative or ἄν with the subjunctive should be used. Many editors emend, but ἄν may generally be defended as potential, expressing the conviction of the agent. Thus, εἵλεσθε ἄνδρας εἴκοσι· τούτους δὲ ἐπιμελεῖσθαι τῆς πόλεως, ἕως ἂν οἱ νόμοι τεθεῖεν you elected twenty men whose duty it should be to care for the State until such a time as in all probability the laws would be made And. 1.81. Cp. S. Tr. 687, I.17, 15, P. Ph. 101d. So ὅταν A. Pers. 450, πρὶν ἄν X. H. 2.3.48,2.4.18.