After the death of the Emperor of Rome, his two sons, Saturninus and Bassianus, ask the masses to determine who should succeed to the throne. The first invokes his natural rights as the first-born son, the second calls upon his virtue and graciousness. They are silenced by the Tribune of the People, Marcus Andronicus, who announces that the people of Rome have elected to the throne Titus Andronicus, a great general who has spent the last ten years and lost twenty-one sons vanquishing Rome 's enemies. Titus enters to great fanfare, trailed by four living sons and two in coffins; he brings with him the captives Tamora, Queen of the Goths, her three sons, and Aaron the Moore. Despite a desperate plea from Tamora, Titus orders, following Roman custom, that Tamora's oldest son be ritually sacrificed in exchange for Titus's own dead offspring.
Marcus offers Titus the scepter of Rome on behalf of the people, but Titus refuses it on account of his age. Instead, he states that Saturninus should be emperor because he is the eldest son; Saturninus returns the favor by taking Lavinia as his empress. Bassianus revolts against this, claiming that Lavinia is betrothed to him. He spirits her away, with the aid of Lavinia's remaining brothers Lucius, Mutius, Quintus, and Martius. When Mutius intercedes with Titus on behalf of his fleeing sister, Titus strikes him down and kills him. It is only after his other sons plead with him that Titus even allows Mutius to be interred in the family tomb.
Publicly humiliated by the loss of Lavinia, Saturninus announces that he will instead take Tamora as empress. The new empress slyly advises him to accept the apologies of Titus and his sons, secretly promising Saturninus that she will help him find another day to exact revenge on the Andronici. The new emperor closes Act 1 by declaring it a love-day and inviting everyone to the court for a feast. Titus offers to organize a hunt for him the next day, and Saturninus accepts.
Act I lays out all the conflicts that will unfurl in bloody splendor through the course of the play: the contest for the crown, the revenge feud between Titus and Tamora, and the foreshadowed rape of Lavinia. The opening speeches of Saturninus and Bassianus represent a Rome that is deeply divided between tradition and virtue--must Rome respect the lineage of the eldest son Saturninus, or should virtuous Bassanius be made its emperor? Titus steps in on the side of tradition, but in doing so he explicitly refuses to "set a head on headless Rome" (I.i.186), leaving Rome rudderless. Rome's fractious status is matched by the subsequent dismemberment of the characters. If the play is understood as a systematic deconstruction and critique of Roman society and ways, then this act displays the first crack.
Even though, with the coronation of Saturninus, the opening quarrel of Act I is seemingly resolved, the act has really planted the beginnings of many new conflicts. To the contrast between traditional right and virtue (as embodied by Saturninus and Bassianus respectively) is added the contrast between Roman civilization and Goth barbarism. When Marcus urges Titus, "Thou art a Roman, be not barbarous" (I.i.378), the implication is that Roman rituals are the bulwark of civilization. However, when Titus turns a deaf ear to Tamora's plea and coldbloodedly sacrifices her oldest son, the very Goths who symbolize barbarism exclaim, "Was never Scythia so barbarous!" (I.i.131) While Tamora pleads for her son's life, Titus does not hesitate to slay his son in the name of honor. The seemingly simplistic distinction between the Romans as civilized and the Goths as barbarous is thus complicated, and we are made to question the violence at the heart of Roman civilization. The high ceremony of the court is a thin veil over savage violence throughout Act I. In the same way, the "love-day" feast is merely a sham, a fact made clear in the mirroring of this opening feast by a closing feast, in which all the rivalries are played out and murder, quite literally, becomes the main course.