Historic city ultimately ignored by an old pictorial publication (3,5)
I believe the answer is:
the beano
'pictorial publication' is the definition.
(comic book)
'historic city ultimately ignored by an old' is the wordplay.
'historic city' becomes 'Thebes' (ancient Egyptian city).
'ultimately ignored' means to remove the last letter.
'by' is a charade indicator (letters next to each other).
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'thebes' with its final letter taken off is 'thebe'.
'thebe'+'an'+'o'='THE BEANO'
(Another definition for the beano that I've seen is " Children's comic".)