'' the lord chancellor ( comic baritone ) george , earl of mountararat ( baritone ) thomas , earl tolloller ( tenor ) private willis , of the grenadier guards ( bass ) strephon , an arcadian shepherd ( baritone ) queen of the fairies ( contralto ) iolanthe , a fairy , strephon 's mother ( mezzo-soprano ) celia , a fairy ( soprano ) leila , a fairy ( mezzo-soprano ) fleta , a fairy ( speaking role/chorus ) phyllis , an arcadian shepherdess and ward in chancery ( soprano ) chorus of dukes , marquises , earls , viscounts , barons and fairies synopsis act i twenty-five years before the beginning of the opera , the fairy iolanthe committed the capital crime ( under fairy law ) of marrying a mortal human .