What medieval and Renaissance features can be found in Shakespeare's Twelfth Night?
One way in which we see both medieval and Renaissance culture represented in Twelfth Night is through the play's connection to the the holiday celebrated on the night after the twelfth day after Christmas, the Feast of Epiphany. The Feast of Epiphany marked the arrival of the Three Wise men who brought gifts to baby Jesus, but the traditions celebrating the holiday actually stemmed from medieval customs that were carried on through Renaissance times, customs that actually go all the way back to Ancient Roman culture.
Literary critics often associate Feste with the medieval tradition of the holiday called the Lord of Misrule ("Feste the Clown (Character Analysis"). The Lord of Misrule was usually a member of the lower class who was selected by chance through eating a bean baked into a slice of cake, and he was appointed to oversee the festivities ("Twelfth Night, the holiday that time forgot"). The festivities, even in Elizabethan times, involved heavy drinking, "masques, revels, defiance of authority, and general foolishness" (Shakespeare's Twelfth Night"). Also in medieval times, the festival known as All Hallows Eve, or Halloween, continued all the way until the Twelfth Night, which also marked the winter solstice festival that was celebrated in Ancient Rome. At winter solstice, the Sun's orbit progresses to the point that the Northern Hemisphere of the earth starts turning to face the sun, while the Southern Hemisphere starts turning away from the sun. Hence the Lord of Misrule, a peasant ruling over society rather than a king ruling over society, represents the "world turning upside down" ("Twelfth Night"). Furthermore, the association with Halloween explains the masquerades and revelries characteristic of both Twelfth Night and Halloween that Shakespeare clearly portrays in his play Twelfth Night.
Feste is considered to be the Lord of Misrule because, while he participates in some of the festivities seen in Twelfth Night, such as the drinking and singing, he also generally remains uninvolved in the play's conflicts, such as the prank played on Malvolio. Instead, Feste becomes the play's moral commentator, even calling Olivia foolish for prolonging her mourning over her brother and calling Duke Orsino fickle, as we see in Feste's line, "...for thy mind is a very opal" (II.iv.79-80).