Describe an event in the play "Twelfth Night" and explain how one of the characters' actions illustrates the following theme:

"True love, with a little help from Fortune, triumphs over man's folly."

In Act V, Scene 1 of "Twelfth Night", a dramatic event unfolds as Sebastian enters the scene, leading to a series of revelations that ultimately allow true love to triumph over the follies of the various characters. Sebastian's appearance results in the revelation of mistaken identities, allowing for the resolution of romantic entanglements and confusion that have persisted throughout the play.

Throughout the play, several characters have been in love or infatuated with others, often with their affections directed towards inappropriate or unattainable objects of their desires. Orsino has been hopelessly in love with the Countess Olivia, who in turn falls for his page Cesario, not knowing that Cesario is actually Viola, a young woman who disguised herself as a man to serve the Duke after being shipwrecked. Mistaken identities and confusion ensue when Viola's twin brother, Sebastian, who she believed had died in the shipwreck, arrives in Illyria and is unknowingly embroiled in the romantic escapades.

In the climactic Act V, Scene 1, the various characters' actions throughout the play come to a head: Antonio, who has rescued and befriended Sebastian, mistakenly believes Cesario to be Sebastian and accuses him of betrayal; Olivia mistakes Sebastian for Cesario and claims him as her husband, which he happily accepts; and Orsino orders Cesario to leave his sight, as Olivia's attachment to Cesario threatens his own desires towards her. It is only when Sebastian appears in this scene that the mistaken identities are clarified, leading to the resolution of these romantic entanglements.

The revelation of the twins' identities allows the characters to see their follies and redirect their affections appropriately. With the help of Sebastian's timely arrival, true love ultimately triumphs: Orsino, upon recognizing Viola's true identity, professes his love for her, and Olivia's marriage to Sebastian is cemented. This event illustrates the theme of "True love, with a little help from Fortune, triumphs over man's folly" as it empowers love to win over the confusion and irrationality that has plagued the characters throughout the play.

In conclusion, Act V, Scene 1 of "Twelfth Night" presents a significant event in which the appearance of Sebastian helps in resolving the mistaken identities that create confusion among the characters. His arrival indirectly leads to the triumph of true love as the characters' follies are exposed and they ultimately find happiness in the correct romantic pairings, showcasing the theme of true love winning over follies with the help of Fortune.