The first aorist in Greek being a " weak " tense, i.e.
After the aorist infinitive clause " Before Abraham was ", properly the perfect clause and tense should follow but does not.
The grammar of the Stoics, gradually elaborated by Zeno, Cleanthes and Chrysippus, supplied a terminology which, in words such as " genitive," " accusative " and " aorist," has become a permanent part of the grammarian's vocabulary; and the study of this grammar found its earliest home in Pergamum.
Thus we find in Homer, but not in the later language (a) The second aorist middle without the " thematic " E or as g - was struck; Ec/Oc-ro, perished; aA-To, leaped.
It will be evident that under this rule the perfect and first aorist subjunctive should always take a short vowel; and this accordingly is the case, with very few exceptions.