Sir Philip Sidney's Arcadia is a prose pastoral narrative about Basilius, the duke of Arcadia, and his family, wife Gynecia, and daughters Pamela and Philoclea.
The first major theme appears early in the work. It is the danger of curiosity. Basilius is a curious fellow. He wants to know the future of his family, so he consults the Oracle at Delphos and receives a stunning prophecy. His wife will take a lover. Pamela will be stolen, and Philoclea will have a love affair. What's more, a foreigner will sit on Basilius's own throne. He is horrified, but now that he knows, he has to act to try to avoid this fate, and he moves his family to the country.
The theme of fate or destiny is at work here as well. Readers may question if these predictions are set in stone or if they may be changed in some way by the characters' actions. Of course, everything the Oracle says comes true, but not at all how Basilius pictures it. Fate or destiny is operative in human life, then, but humans cannot tell how things will actually work out until they happen.
Arcadia also explores the theme of identity and misrepresentation. Several characters disguise themselves in this story. Pyrocles falls in love with Philoclea and, to get close to her, disguises himself as the Amazon Zelmane. This leads to all kinds of misunderstandings, for Basilius falls in love with Zelmane.
Gynecia learns Pyrocles's true identity and also falls in love with him. Philoclea cannot figure out why she is so attracted to a woman, and she is quite horrified by it. Musidorus also disguises himself as a shepherd to be close to his beloved Pamela. Gynecia even dresses up as Zelmane and fools her husband at one point. In the end, everyone's true identity is revealed, but much confusion and suffering happens in the meantime because of the misrepresentation.
Further, Arcadia reflects on the theme of the nature of love. Readers are led to ponder what love really means. Some characters appear to be merely infatuated with each other. Others seem to have the makings of a solid, loving relationship. Yet many obstacles stand in the way of love, and these only make love, or at least desire, grow stronger. Jealousy raises its head even among the closest of relatives. Finally, though, the "right" couples get together, and the story has a happy ending and contains the hope that true love does exist.
Finally, Arcadia presents the theme of reason versus passion. Many of the characters in this story are driven by passions that seem to shut down their ability to reason, and this gets them into serious trouble. If Basilius, for instance, would not have been so terrified of the prophecy and given in to his fear, he and his family might not have struggled so much. If Pyrocles and Musidorus had been led more by their reason than their passions, they, too, might have avoided a great deal of difficulty. Yet, of course, we wouldn't have such a delightful story to enjoy.