29.9 As we discussed earlier, the fundamental dichotomy for VOICE was between ACTIVE and MIDDLE. As a result, no distinct PASSIVE forms ever developed for the PRESENT tense; if the need for the PASSIVE voice arose, the MIDDLE endings were used, and the voice of the verb determined in part by context within a sentence. It makes sense, then, that the AORIST also has ACTIVE and MIDDLE endings. What may not be expected is that there also arose a third set of endings for the AORIST, which most modern grammars call AORIST PASSIVE endings. For reasons discussed shortly, a better term for the resultant verb form is the THETA AORIST (-θη- / -η-).
To form the THETA AORIST, the following formula is used:
- ἐ + verb stem + θη + athematic secondary endings
Sometimes the addition of –θη spurred changes to the verb stem (e.g., the THETA AORIST of ἄγω is ἤχθην). For other verbs, adding –θη created unwanted complexities in pronunciation, so only –η– was added (e.g., the theta aorist of γράφω is ἐγράφην). Since these and other such variations to the formation of the THETA AORIST are possible, the THETA AORIST is listed as the SIXTH PRINCIPAL PART of typical verbs. Generally speaking, however, the THETA AORIST is easy to recognize and parse because of its distinctive –θη marker and regular personal endings.
(cf. S 383)
