Richard III was probably written between 1591 and 1594, about the time many of the history plays were being written and performed. This play "completes the action of the four-play series begun with 1 Henry VI" (Bevingtion 628).
The publication history of Richard III is quite complex; two very different versions of the play were printed between 1597 and 1623 (date of the First Folio) (Mowat and Werstine xlvii): "the versions of Richard III crisscross: the first printed version, almost all scholars agree, provides a second state of the play, and later printings of the second state, in turn, influenced the printing of the play in its first state" (xlviii). The first printing was a 1597 Quarto version (Q); the second (though probably of an earlier version of the play) was the 1623 First Folio edition (F). However, there were six printings of the Q edition between the first printing and the appearance of the play in the First Folio. Modern editors base editions on the First Folio, one of the Quarto editions, or some combination of the two. Some also integrate changes (considered corrections) from Quartos into an edition based mainly on the First Folio. You should read the introduction to your version of the play to determine what decisions the editor has made, because your text may be slightly different from that quoted here or from other versions used by your classmates.
According to Bevington, Richard III was based on a number of histories. The most famous is Holinshed's Chronicles (1578), but there is also evidence that Shakespeare was influenced by Edward Hall's Union of the Two Noble and Illustre Families of Lancaster and York (1542), Fpolydore Vergil's Anglica Historia (1534), and Thomas More's The History of King Richard the Third (1557) (628-9).
The Henry IV plays and Richard III treat a period of civil strife in English history known as the "Wars of the Roses." These wars were between the families of Lancaster and York. The action of this play begins in 1461, just after the York family, lead by Richard's older brother Edward, have finally wrested the throne from the Lancaster family. Much of the complexity during the reign of Edward (he was removed from and restored to his throne during this reign) is omitted from the play, which focuses instead on Richard's rise to power, and his eventual defeat at the hands of Henry Tudor, who was the ancestor of Elizabeth I, the reigning monarch at the time of Shakespeare's play.
Richard III is concerned with civil authority and the power of deception. Richard is one of the blackest of Shakespeare's villains, often compared with Iago (from Othello) or Edmund (from King Lear): villains who are evil beyond their motivations. The character of Richard makes complex statements about language, reputation, and rhetorical presentation. Because Richard is ugly and deformed, and because of the tradition of connecting physical appearance with inner character, Richard's ability to gain the trust of others and to deceive deserve special attention. This play also presents strong commentary about rulers and the balance between the personal desire for power and the ability to lead a society responsibly.
Because it is a history play, Richard III has fewer prominent female characters than other plays studied this term; often women serve merely as rhetorical sounding boards to display Richard's persuasive dexterity (the interview between Anne and Richard in I.ii, for example). The character of Margaret, a left-over Lancaster who haunts the York reign, though, provides an opportunity to think about what power might be available to the powerless, and the role of women in general, which can be further considered in the roles of Anne and Elizabeth, the wife of Richard's brother Edward.
Richard III, perhaps surprisingly, also has a vein of the mystic: particularly in terms of dreams, predictions, and curses. These experiences complicate the political logic of the play and perform interesting plot functions. This play should be considered, too, from the perspective of Shakespeare's audience, for whom the action would be past and well-known history.
Bevington, David. The Complete Works of Shakespeare, 4th ed. New York: Longman, 1997. Pp. 628-30.
British Library. "Shakespeare's Quartos: Richard III." N.d.
Mowat, Barbara A. and Paul Werstine. "An Introduction to this Text." Richard III. New York: Washington Square Press, 1992. Pp. xlvii-lx.