This title became the traditional title of the heir apparent to the English throne. Prince Edward was not born heir apparent, but became so when his older brother Alphonso died in 1284; Prestwich 1997, pp. 126–7. Prestwich, Michael (1997). Edward I (updated ed.). New Haven: Yale University Press. ISBN0300072090.
Barrow 1965, pp. 206–7, 212–3 Barrow, G. W. S. (1965). Robert Bruce and the Community of the Realm of Scotland. London, UK: Eyre and Spottiswoode. OCLC655056131.