The Theaetetus is one of the few works of Plato that gives contextual clues on the timeline of its authorship: The dialogue is framed by a brief scene in which Euclid of Megara and his friend Terpsion witness a wounded Theataetus returning on his way home after from fighting in an Athenian battle at Corinth, from which he apparently died of his wounds. Euclid tells his friend that he has a written record of a dialogue between Socrates and Theaetetus, which occurred when Theaetetus was quite a young man. The dialogue is then read aloud to the two men by a slave owned by Euclid.
The exact timeline of which battle at Corinth has been a matter of some disagreement between scholars: it has generally been presumed that the battle occurred in 369 BC; when Theaetetus would have been in his late forties, but more recently, scholars including Debra Nails have argued that the battle referenced in the dialogue was a different battle in Corinth that occurred much earlier, in 391 BC, when Theatetus would have been in his late 20s.[1]
As far as internal characteristics, the dialogue is considered to be similar to the "earlier" dialogues of Plato, such as the Euthyphro or the Crito, in that Plato's Socrates discusses the nature of knowledge in the Theaetetus without giving any of his own views, and the dialogue ultimately ends in aporia without a satisfying answer. However, it also resembles many of the more philosophically complex "later" dialogues such as Parmenides, Phaedrus and the dialogues Sophist and Statesman which serve as a narrative sequel.
