1st Aorist Middle Voice

Compare:

Present Tense						Aorist Tense
I	travel		πορεύ	ομαι		I	travelled		ἐπορευσ	άμην
you	travel		πορεύ	ει / ῃ		you	travelled		ἐπορεύσ	ω [ασο]*
he	travels		πορεύ	εται		he	travelled		ἐπορεύσ	ατο
we	travel		πορευ	όμεθα		we	travelled		ἐπορευσ	άμεθα
you	travel		πορεύ	εσθε		you	travelled		ἐπορεύσ	ασθε
they	travel		πορεύ	ονται		they	travelled		ἐπορεύσ	αντο

  Note  

The aorist (simple past telling that something happened, full stop), is actually easier than the present tense, as far as endings are concerned. There are no exceptions, no contractions (!!!) of stem vowel + endings.
Only 2nd person singular, which should be ἐπορεύσασο plays odd man out:
Because sigma between 2 vowels (in endings) usually disappears, we are left with
ἐπορεύσαo contracting to ἐποπεύσω.
Just like 2nd aorist ἐγένεσο (you became) contracted to ἐγένου and
Just like 2nd aorist εἵλεσο (you chose) contracted to εἵλου because
εσο, dropping the σ left εο contracting to ου.  

Some more 1st aorist middle forms:

δέχομαι - ἐδεξάμην, I received, accepted
εὔχεται - ηὔξάτο, He prayed
πότε [ὁρμάεσαι] ὁρμᾷ; - πότε ὠρμήσω [ὡρμήσασο]; When did you set out?
τίνι ἡγεῖτο; - τίνι ἡγήσατο ἐκεῖσε; Whom did he lead there?
παρασκευαζόμεθα - εὐθύς παρεσκευασάμεθα. We got ready at once.
ἀποκρίνεσθε - διὰ τί οὐκ ἀπεκρίνασθε; Why did you not answer?
[θεάονται] θεῶνται - τὴν θεὸν ἐθεάσαντο. They looked at the goddess. (in front of the temple)