Imperfect of είμαι (ήμουν) | Greek Grammar

Once you can say "I am," the next thing you need is "I was." In Greek that is ήμουν — the past of είμαι. It carries the same enormous load in the past that είμαι carries in the present: who you were, how you felt, where you were, what existed. And there is a piece of very good news hidden inside it. Ordinary Greek verbs split their past into two tenses, an imperfect and an aorist, and choosing between them is one of the hardest things about the language. είμαι has no aorist at all — its single past, the imperfect, does every job. There is nothing to choose. Learn these six forms and the entire Greek past of "to be" is yours.

The paradigm

Person	Form	Reading	Meaning
εγώ	ήμουν	ímun	I was
εσύ	ήσουν	ísun	you were (sg)
αυτός/-ή/-ό	ήταν	ítan	he / she / it was
εμείς	ήμασταν	ímastan	we were
εσείς	ήσασταν	ísastan	you were (pl/formal)
αυτοί/-ές/-ά	ήταν	ítan	they were

Two features leap out, and both echo the present tense you already know.

First, ήταν does double duty, exactly the way είναι does in the present: the same word means "he/she/it was" and "they were." Greek simply does not distinguish third singular from third plural in this verb, so the subject tells you which is meant:

Το δωμάτιο ήταν κρύο και σκοτεινό.

to dhomátio ítan krío ke skotinó

The room was cold and dark.

Τα δωμάτια ήταν κρύα και σκοτεινά.

ta dhomátia ítan kría ke skotiná

The rooms were cold and dark.

Second, notice the -μουν / -σουν / -ταν / -μασταν / -σασταν shape. These are past mediopassive endings — the same family that gives είμαι its odd -μαι / -σαι / -ται in the present. είμαι patterns like a deponent throughout: mediopassive in form, but simply meaning "to be." You will meet these very endings again on the past of verbs like έρχομαι (ερχόμουν "I was coming") and θυμάμαι (θυμόμουν "I remembered"), so the effort you spend here pays off twice.

The colloquial variants

Everyday speech adds an optional -α to the singular and freely shortens the plural. All of these are correct; the differences are register, not grammar:

1sg ήμουν / ήμουνα — the fuller ήμουνα is a touch more colloquial (informal).
2sg ήσουν / ήσουνα (informal) for the longer form.
3sg/3pl ήταν / ήτανε — ήτανε (informal).
1pl ήμασταν / ήμαστε, 2pl ήσασταν / ήσαστε — both members of each pair are standard; ήμαστε and ήσαστε are, if anything, the more traditional demotic.

None of these is a mistake. What would be a mistake is inventing a past from the present stem — there is no ×είμουν (see the common errors below).

What ήμουν is for

It covers every job the present είμαι does, shifted into the past.

State or condition — how someone was or felt. The adjective agrees with the subject in gender and number:

Ήμουν πολύ κουρασμένη χθες το βράδυ, γι' αυτό έφυγα νωρίς.

ímun polí kurazméni chthes to vrádhi, yaftó éfigha norís

I was very tired last night, so I left early.

Όταν ήμουν μικρός, φοβόμουν το σκοτάδι.

ótan ímun mikrós, fovómun to skotádhi

When I was little, I was afraid of the dark.

Identity or profession — what or who someone was. Just as with the present, the word after ήμουν/ήταν stays in the nominative:

Ο παππούς μου ήταν δάσκαλος σε ένα μικρό χωριό.

o papús mu ítan dháskalos se éna mikró chorió

My grandfather was a teacher in a small village.

Location — where someone or something was:

Ήμασταν στην Αθήνα εκείνο το καλοκαίρι, μέναμε κοντά στην Ακρόπολη.

ímastan stin Athína ekíno to kalokéri, méname kondá stin Akrópoli

We were in Athens that summer; we were staying near the Acropolis.

Ήσασταν κι εσείς στο πάρτι; Δεν σας είδα καθόλου.

ísastan ki esís sto párti; dhen sas ídha kathólu

Were you at the party too? I didn't see you at all.

Age — Greek gives past age the same way it gives present age, with a form of είμαι plus χρονών:

Πόσο χρονών ήσουν όταν πρωτοπήγες σχολείο;

póso chronón ísun ótan protopíyes scholío;

How old were you when you first went to school?

Plain "it was" — describing a whole situation, weather, a day. Here ήταν is the workhorse of every story you tell:

Ήταν μια υπέροχη μέρα, ο καιρός ήταν τέλειος.

ítan mia ipérochi méra, o kerós ítan télios

It was a wonderful day; the weather was perfect.

Τα παιδιά ήταν κουρασμένα και νυσταγμένα μετά το ταξίδι.

ta pedhiá ítan kurazména ke nistaghména metá to taksídhi

The children were tired and sleepy after the trip.

💡

Because είμαι has no aorist, you never have to make the imperfect-vs-aorist decision that haunts every other Greek verb. Whenever the meaning is "was" or "were" — a state, a description, a location, an identity — ήμουν is automatically the right and only choice.

The complement stays nominative

This is the one point where English intuition misleads. English says "It was me," "That was him," with object pronouns, and speakers of many languages expect the noun after "was" to look like an object. Greek does not agree: ήμουν and ήταν link two things that are the same, so the complement keeps the nominative, exactly like the subject. You say Ήταν ένας καλός γιατρός (nominative ένας καλός γιατρός), never ×Ήταν έναν καλό γιατρό. The complete rule — for nouns, adjectives, and pronouns — lives on the predicate nominative.

Negation

Put δεν directly in front of the verb, not όχι (which stands alone as the answer "no"):

Δεν ήμουν σίγουρος αν έπρεπε να έρθω ή όχι.

dhen ímun síghuros an éprepe na értho i óchi

I wasn't sure whether I should come or not.

Πού ήσουν όλο το πρωί; Σε έπαιρνα τηλέφωνο και δεν απαντούσες.

pu ísun ólo to proí; se éperna tiléfono ke dhen apandúses

Where were you all morning? I kept calling you and you didn't answer.

Common Mistakes

1. Building the past from the present stem. The past of είμαι is not ×είμουν, ×είσαι-past, or anything derived from είμ-. It is the suppletive ήμουν; you simply learn it.

❌ Είμουν άρρωστος όλη την εβδομάδα.

Incorrect — the past of είμαι is ήμουν, not a form built from the present stem.

✅ Ήμουν άρρωστος όλη την εβδομάδα.

ímun árostos óli tin evdhomádha

I was ill all week.

2. Putting the complement in the accusative. After ήταν a predicate noun is nominative, just as in the present.

❌ Ο πατέρας μου ήταν έναν καλό γιατρό.

Incorrect — after ήταν the noun stays nominative: ένας καλός γιατρός.

✅ Ο πατέρας μου ήταν ένας καλός γιατρός.

o patéras mu ítan énas kalós yatrós

My father was a good doctor.

3. Negating with όχι instead of δεν. A verb is negated with δεν; όχι is the free-standing "no."

❌ Όχι ήμασταν στο σπίτι, ήμασταν έξω.

Incorrect — negate the verb with δεν: Δεν ήμασταν στο σπίτι.

✅ Δεν ήμασταν στο σπίτι, ήμασταν έξω.

dhen ímastan sto spíti, ímastan ékso

We weren't at home, we were out.

4. Leaving the verb in the present when the time is past. A past-time word like χθες forces ήταν, not είναι.

❌ Χθες είναι πολύ κρύο έξω, γι' αυτό δεν βγήκαμε.

Incorrect — a past time needs the past tense: Χθες ήταν πολύ κρύο.

✅ Χθες ήταν πολύ κρύο έξω, γι' αυτό δεν βγήκαμε.

chthes ítan polí krío ékso, yaftó dhen vyíkame

Yesterday it was very cold outside, so we didn't go out.

Key Takeaways

The past of είμαι is the imperfect ήμουν, ήσουν, ήταν, ήμασταν, ήσασταν, ήταν — and it is the only past, because "to be" has no aorist.
The single form ήταν covers both "he/she/it was" and "they were," mirroring είναι in the present.
The endings are the past mediopassive set (-μουν / -σουν / -ταν …), reused later on έρχομαι, θυμάμαι and other deponents.
Colloquial -α variants (ήμουνα, ήσουνα, ήτανε) are correct informal forms, not errors — but ×είμουν, built from the present stem, is genuinely wrong.
The complement stays nominative (Ήταν δάσκαλος), and negation is with δεν (Δεν ήμουν).

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