Original: Only seven tragedies have survived intact: The Persians, Seven against Thebes, The Suppliants, the trilogy known as The Oresteia, consisting of the three tragedies Agamemnon, The Libation Bearers and The Eumenides, and Prometheus Bound (whose authorship is disputed).
Simplified: Only six tragedies have survived intact: The Persians, Seven against Thebes, The Suppliants, the trilogy known as The Oresteia, consisting of the three tragedies Agamemnon, The Libation Bearers and The Eumenides.