Board Thread:Naruto Discussions/@comment-28846843-20160625201600/@comment-9782468-20160702194647

Actually he was noted as the strongest kage during his reign, so he was stronger than the 3rd Raikage.

You say just let it be, but just letting it be is basically ignoring what Kishi wrote even though there isn't any evidence against Hiruzen being immensely powerful in his prime.