'Legitimacy, Illegitimacy and Sovereignty in Shakespeare's British Plays', presented to the University of Manchester in 2011 for the degree of Doctor of Philosophy by Katie Pritchard, demonstrates how Shakespeare participates in an early modern 'discourse of legitimacy' as described by Robert Zaller. This thesis, however, proposes an interrelated discourse of illegitimacy that is of equal importance to the discourse of legitimacy. A continuum or spectrum of legitimacy values is hypothesised, and seventeenth century optical illusions known as the curious perspective are used as a visual model that defines the inseparable nature of illegitimacy and legitimacy. Illegitimacy was a state traditionally defined as restrictive, and stereotyped as stigmatised by historians. Examination of the situation of early modern illegitimates in England, however, suggests a more inclusive attitude to illegitimates than has been previously acknowledged.The plays under discussion are under studied as a group; the thesis examines the British-set history and romance plays, defining them as 'British plays'. This is because one of the central implications of the discourse of (il)legitimacy is that it forms an evaluation of nationhood in early modern England and Britain. Using recent reconsiderations of national identity during the sixteenth and seventeenth centuries, this thesis identifies a strong national sentiment in Shakespeare's drama. The change from an Elizabethan English monarchy to a Jacobean British one instigated a reconsideration of what national identity might entail, using the discourse of legitimacies and illegitimacies to evaluate this developing concept. 'Legitimacy, Illegitimacy and Sovereignty in Shakespeare's British Plays' identifies how these discourses also link to other related themes in the British plays. The concept of sovereignty, as the thesis title suggests, is strongly linked to ideas of legitimacy and illegitimacy, with examples of the discourse used in this context drawn from Shakespeare's works and a wider range of texts. Identification of the sovereign with national allegiance, to a certain degree, links these themes, yet Shakespeare also dramatises an independent national sentiment in the British plays, revealing developing nationhood onstage. National sentiment also infuses another area in which the discourse of (il)legitimacy is used by Shakespeare; the legal debates of the era are reflected in the British plays; a contemporary conflict between common and civil law, and the aim of many lawyers to rediscover an ancient constitution of Britain, especially in the area of patrilinear inheritance, is acknowledged throughout in Shakespeare's use of legitimacy images and metaphors.As 'metaphors' suggests, illegitimacy is an increasingly conceptual issue in the thesis. Shakespeare uses ideas of illegitimacy to inform many areas; in particular a kind of validity or truth. A chapter on metaphorical illegitimacy demonstrates how illegitimacy and legitimacy language is suggestive of other issues. The invalidity of a usurped kingdom, a false kingship, is negotiated through illegitimacy discourses in Richard II, as the attempt to validate leadership in the second tetralogy is articulated with a discourse of totalising masculine legitimacy. 'Legitimacy, Illegitimacy and Sovereignty in Shakespeare's British Plays' works within a contextual framework to locate the language and concepts Shakespeare dramatises in a wider environment, reflecting the issues of law, sovereignty and nation that existed in early modern English and British society.