I participated in the AFD discussion, but this is not my specialism.  Some one else has drawn my attention to this warring, which appears to be the result of some one not accepting the outcome of the AFD, claiming the consensus was Merge rather than Keep.  The proper whay to dispute the closure of an AFD is a deletion review, but that is not what has been done.  Having decided that the outcome was to Keep, you should be protecting the full text of the article, not the redirect, and I would therefore suggest that you revert to the full article and protect that.  During that period of protection, discussion can take place on its talk page as to what should happen.  That is difficult while it is a redirect, becasue of the automatic transfer to the redirect destination.  I know how to get around that but others may not.  The addition of a paragraph to Mare Nostrum is also appropriate, but this should be linked by a "main" template to that on Italian Mare Nostrum.  That is a much fuller article, dealing with the Italian Naval War in the Mediterranean suring WWII.  I am copying this to its talk page, which is a much better forum for the discussion.