‘Twelfth Night character heading off North with article’ – making of an opera? (8)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

definition: IOLANTHE is a comic opera by Gilbert and Sullivan [V]- IOLA =character in Shakespeare’s Twelfth Night , with the first letter/”heading” taken “off”; plus N (North) + THE (definite article)