Sophocles was an ancient Greek poet and one of three ancient Greek tragedians whose plays have survived. His plays belonged to the period after Aeschylus and earlier of Euripides. Based on the information provided by Suda, a 10th century encyclopedia, Sophocles wrote 123 plays during his lifetime, out of which only seven have survived in a complete form. These plays are Ajax, Antigone, Trachinian Women, Oedipus the King, Electra, Philoctetes and Oedipus at Colonus. It was believed that he remained the most celebrated playwright in the dramatic competitions of the city-state of Athens held during the religious festivals of the Lenaea and the Dionysia. Sophocles participated in thirty competitions, of which he won 24 and never went below second place in the rest. Among his plays, the two most famous tragedies, Oedipus and Antigone are generally known as the Theban plays, even though each play belonged to a part of a different tetralogy. Sophocles greatly influenced the drama. His main contribution was the addition of third actor which reduced the importance of the chorus in the presentation of the plot. A crater on the surface of Mercury has been after this ace Greek poet and playwright.