[1] The meaning of the three crowns is not certain,[2] but one possibility is that they may represent three of the medieval Hiberno-Norman lordships in Munster; the O'Briens (Thomond), the Butlers (Ormond) and the Fitzgeralds (Desmond).

[3] Other sources suggest that the arms (dark blue, three antique crowns Or) are derived from the short-lived dukedom of Ireland created for Robert de Vere in 1386.

[6] The Irish province of Munster has been heraldically symbolised by three golden antique crowns on a deep blue shield since at least the 17th century.

[citation needed] While first recorded in the 17th century as a heraldic representation of Munster, the three crowns motif was reputedly "brought into Ireland with the Normans at the earliest".

In the case of the 'king-bishops' of Cashel, the placing of the antique crown on their crozier was a symbolic assertion of their political sovereignty over Munster.