that allows her to do what is right. This is theirony of the play. Antigone dies having done the right thing and having fulfilled her duty as sister and princess.

The Ancient Greeks placed a lot of value on things like courage, loyalty, and faith. Antigone has all three in abundance, something that cannot be said for other characters in the play. The play is set just after a civil war between Oedipus’s two sons, Eteocles and Polynices. The princes of Thebes were Antigone’s brothers, and she felt loyalty and love toward them both. However, because Polynices brought a foreign army against Thebes in an attempt to win the throne, he is sentenced to have his body left unburied.

A dead body left unburied is a big deal. The Ancient Greeks believed that letting someone go unburied was essentially to sentence them to eternally wander the shores of the River Styx. It was not only a terrible thing to do but also a sin against the gods. Antigone defies the edict and buries her brother, choosing to give him safe passage in the afterlife. Her choice to rebel is dangerous, but she sees it as her duty. At the start of the play, she asks her sister Ismene to help her bury Polynices, but Ismene says no. Antigone responds,

You have made your choice, you can be what you want to be.
But I will bury him; and if I must die,
I say that this crime is holy: I shall lie down
With him in death, and I shall be as dear
To him as he to me. It is the dead
Not the living, who make the longest demands:
We die for ever…
You may do as you like
Since apparently the laws of the god mean nothing to you. (Prologue)

It is clear from this passage what Antigone represents and why she is a hero. She is courageous. knowing that burying her brother means she risks death but embracing that possibility as necessary to fulfill her duty. She shows her loyalty in doing the thing that might bring her most danger, even as her sister says she will not help—even going as far as to disown her sister for her betrayal of Polynices. Lastly, she shows her faith, understanding that not burying Polynices would be an insult to the gods, as their laws dictate that people should be buried.

The reason Antigone fits the bill of Greek tragic hero is that her stubborn resolve to bury her brother becomes her downfall. While she could avoid her tragic ending, she embraces it and instead almost runs toward it. She is proud of the fact that she is doing the right thing, and she angers Creon by declaring so boldly that what she is doing is right. Ultimately, her hamartia is her stubborn pride.

The term "tragedy" had a rather specific meaning in ancient Greece. It was a type of play evolving from the choral ode, normally performed at religious festivals. All extant tragedies share the fact that they were staged with a maximum of three individual actors. Scenes alternated between episodes in which actors talked with each other or with the chorus, and choral odes in which the chorus sung and danced in a flat circular "orchestra" or "dancing place" at the front of the stage. Antigone conforms to this definition and was initially performed at a festival honoring the god Dionysus. Like most (but not all) tragedies, it deals with legendary events concerning noble or royal characters and has an unhappy ending. All ancient sources refer to it as a tragedy.

In his Poetics, Aristotle gives a description of what he thinks are the characteristics of the ideal tragedy. Notably this includes a protagonist who has a flawed but noble character, a reversal of fortune that evokes fear and pity, and a plot of a certain magnitude or grandeur. One should note, however, that these characteristics do not define the nature of tragedy, but are instead Aristotle's individual (and very influential) assessment of what makes a good tragedy. 

Antigone is a tragedy because, following Aristotle's definition of a tragedy, it imitates an action that has serious consequences. The play is about the ability or inability of a citizen to defy the wishes of the state and to prioritize one's family over the state. There are real issues that have serious consequences. The play also offers a catharsis, or a purging of emotions after first causing feelings of pity and fear. In Antigone, the audience feels pity and fear about Creon's persecution of Antigone, and through these emotions, the audience experiences catharsis. 

The hero in Antigone also has tragic flaws that bring about his or her downfall. These flaws are typically a form of hamartia (which means a human flaw), and the hero is not brought down because he or she is evil. Both Antigone and Creon, it could be argued, have flaws that result in their downfall, as they are both stubborn and cannot see the other side of the argument in which they are engaged (about whether or not Antigone has the right to bury her brother, who was deemed a traitor to the state). 

In addition, the plot of Antigone involves a reversal, or peripeteia, in which a person is brought down from a high position to a low one. Creon experiences this reversal to a greater extent than Antigone does, and he also experiences anagnorisis, or the recognition that his refusal to let Antigone bury her brother has led to destruction and sorrow. 

The title character is the tragic hero(ine) of Antigone. She exhibits all the characteristics of a classic tragic hero. As the daughter of Oedipus, she is royal. And she obviously meets a tragic fate, being sentenced to death by her uncle, and committing suicide just before she is to be rescued. Her tragic flaw is a little more tricky, because she is clearly a sympathetic character. But Greek audiences would have understood that she had the tragic flaw of hubris, in that she felt justified in defying the dictates of Creon, the king, based on her adherence to what she views as a higher law. She is unrelenting in her determination to give her brother a proper burial, because she feels a family obligation to do so, and because she believes it is the right thing to do. While this seems admirable to us (and Sophocles' audiences) it would also have been understood as a somewhat reckless action that would have mortal consequences for Antigone. This is especially the case because Antigone makes a point of making her actions public. When Ismene swears that she will tell no one of her sister's plans, Antigone responds:

Oh, denounce it! I will hate you the more
if you don't tell these things to everyone.

Her behavior demonstrates that she is driven by pride and self-confidence in addition to her deep devotion to her family. Her unyielding nature, while admirable, is her undoing. As the Chorus observes, just after Antigone has confessed her "crime" to Creon:

She's clearly the fierce
daughter of a fierce father; she doesn't know to bend with the wind.

Antigone can certainly be identified as a tragic heroine in the play by Sophocles that bears her name. By the time the play opens, Antigone has already experienced more than her share of tragedy. She is the child of an incestuous relationship between her parents, Oedipus and Jocasta. They didn't know it when they married, but Jocasta was actually Oedipus's mother. She ended up killing herself. Oedipus blinded himself in grief and anguish. Antigone and her siblings were left shattered.

Antigone then wandered with her blind father for many years, caring tenderly for him. Meanwhile, her two brothers began feuding with each other, and one attacked Thebes in an effort to regain the rule of the city. He has just been defeated when Antigone opens. In fact, both of Antigone's brothers have died in the fight, and King Creon has ordered that the "traitor" Polyneices should be left to rot, unburied on the battlefield.

Antigone will not allow this unjust and compassionless order to stand. She declares that she will bury her brother. She cannot stand to leave him lying there as food for the birds and dogs. She will defy Creon's order even if the price is her own life. And, indeed, she does. Antigone performs the customary rites for her brother as well as she can. When she is caught, she stand courageously and unrepentantly before Creon and accepts her punishment, unjust and horrific as it is, of being buried alive.

Creon actually repents in the end and hurries to release Antigone, but it is too late. She has hung herself to escape the horror of her fate.

Let's think for a moment about the characteristics of a tragic hero or heroine as defined by Aristotle and see how they apply to Antigone. First, a tragic hero or heroine is virtuous and therefore sympathetic to the audience. We can certainly say this of Antigone. She stands up for what is right no matter what the consequences, and we cannot help but admire her for it.

But a tragic hero or heroine is also flawed. Antigone is not perfect. She is stubborn and tries to get her sister to go along with her (playing a pretty good guilt trip in the process). She also gives in to despair at the end of the play and kills herself. Finally, a tragic hero or heroine suffers some kind of reversal of fortune. This is certainly true of Antigone, who has gone from princess and favored daughter to criminal.

Antigone is tragic in so far as she represents one end of a tragic collision.  She does not follow the traditional notion of tragedy in that she does not endure much in way of transformation or a sense of evolution of her character.  In this respect, her father, Oedipus, is far more tragic than she is because he must endure a transformation of character whereby he understands his own pathetic nature, a key element of tragedy.  Antigone does not have to endure this.  She stands tall in her beliefs and accepts them no matter what.  Her demise is only spelled out because she clings to her beliefs.  She gets the label of being a tragic heroine because she represents one end of the collision between the desires of the individual when they come in conflict with those of the state.  I would actually go as far to say that if Antigone is considered tragic for clinging to her beliefs and suffering for them, Creon is also a tragic figure.  If nothing else, he suffers a heck of a lot more than she does and loses more than Antigone.  Additionally, he is compelled to live and to see the results of his actions, making him more tragic than Antigone in my mind.