The ancient theatre of Cassope is built in the southern foothills of Zaloggo and overlooks the peninsula of Preveza, the Ambracian Gulf, the Ionian Sea, the island of Lefkada and the Acarnanian mountains.

It was originally built in the 3rd BCE. Two polygonal retaining walls, reinforced with buttresses, support the two ends of the koilon (the seating area or auditorium), which is separated by an intervening diazoma (horizontal walkway) into two main seating zones, the lower one consisting of twenty-four rows of stone seats and the upper one of twelve rows.

At the top of the auditorium, a wider walkway is protected by an outer wall that has an opening, possibly facilitating the exit of spectators from the upper part of the theatre.

Eleven stairways divide the theatre into ten kerkides (vertical seating zones), the ones at the two edges having half the width of the others.

The orchestra of the theatre, is unique, since it does not form a full circle, but an arc greater than a semicircle.

The scene (backstage building) is rectangular, flanked by two paraskenia (wings) which extend on either side of the orchestra and contain the proskenion (stage), which has six columns on its facade.

The theatre would have had a seating capacity of approximately 5.000 – 6.000 people.