The story of the persuasion of Achilles into battle is drawn from Homer's Iliad (perhaps in the translation by George Chapman), and from various medieval and Renaissance retellings, whereas the story of Troilus and Cressida is a medieval chivalric romance that is not part of Greek mythology.
Shakespeare drew on a number of sources for this plotline, in particular Chaucer's version of the tale, Troilus and Criseyde, but also John Lydgate's Troy Book and Caxton's translation of the Recuyell of the Historyes of Troye.[13]
The two storylines of Troilus and Cressida—the love story of the title characters, and the warfare mainly around Hector, Ajax and Achilles—have completely different origins. While the warfare is of ancient origins and is at the core of the Troy saga in the Homeric epics, especially the Iliad, the story of Troilus and Cressida is part of the narrative material of the Middle Ages: it does not come from Greek mythology, but belongs to the narrative motifs found in the medieval retelling of popular material.
At its first appearance this new storyline is an embellishment by Benoît de Sainte-Maure in his Roman de Troie, which was written for the court of King Henry Plantagenet as a kind of "prince mirror".[14] For his part, Benoît extended stories from Dictys Cretensis and Dares Phrygius from the late Roman period, which entwine around the Iliad material, with his own romantic sub-plot. The Roman de Troie was in turn a source for Boccaccio's "Il Filostrato", which was the main source for Chaucer's poetry Troilus and Criseyde (c. 1380); Shakespeare knew Chaucer's works very well.[15] Other versions of the material, such as John Lydgate's "Troy Book" and Caxton's "Recuyel of the History of Troy", were at the time of Shakespeare in England in circulation and probably known to him.[15][16]
The story was a popular one for dramatists in the early 17th century and Shakespeare may have been inspired by contemporary plays. Thomas Heywood's two-part play The Iron Age also depicts the Trojan War and the story of Troilus and Cressida, but it is not certain whether his or Shakespeare's play was written first.[17] In addition, Thomas Dekker and Henry Chettle wrote a play called Troilus and Cressida at around the same time as Shakespeare, but this play survives only as a fragmentary plot outline.[18]
