Don't just delete the article. Keep it with the requested attribution until it can be
rewritten. We don't want to destroy the evidence of the Wikipedia complying with such
requests. It'll be useful for establishing a pattern of compliance in any future
defence.
The history is not a great concern. It's not intended to be part of the publication.
Only the current Wikipedia page has that intent and that will remain true so long as
search engines don't index the history pages. Something which isn't intended for
publication and is documenting compliance with a legal notice is unlikely to be copyright
infringement.
The request has now been honored so it's time to reply to the author saying something
along the lines of:
"Sorry about that. We've added the credit you requested.
Unfortunately, we will have to rewrite the article to remove your work. Our fundamental
objective is to create an encyclopedia all or part of which can be used for any commercial
or non-comercial purpose. Part of means that someone could edit out the credit to you. To
do this we use the GFDL license (link to it).
If you feel that you are willing to license this part of your work under the GFDL,
accepting the way it works, please let us know. If not, please once again accept our
apologies for the inconvenience and check back in a week to ensure that the revised
version doesn't infringe your rights in any way, assuming that someone removes the
credit to you. If it does, please let us know what further changes are needed.
We have a page at
http://www.wikipedia.org/wiki/Comparative_military_ranks which is an
index to many descriptions of ranks. We'd appreciate it if you could review any of
those which may infringe your rights and let us know if any do, so that we can carry out
the same process on any of them which require it.
We keep records of past versions of our articles, which aren't part of the normal
publication but are available to those who specifically request them. You can see the
history of this article at
http://www.wikipedia.org/w/wiki.phtml?title=Commodore_(rank)&action=his… and one of
the older versions at
http://www.wikipedia.org/w/wiki.phtml?title=Commodore_(rank)&diff=0&… .
While we prefer to keep those for our records, so we can demonstrate compliance with your
request, please let us know if you would like us to make it impossible for those working
on building the Wikipedia to see those working documents.
Finally, if you wish to revise the article to meet your requirements, you can do so
yourself at any time by clicking on the edit link at the top of that or any other
Wikipedia page which has an edit link. Please note that any revised version will be
released under the GFDL, so take care not to include any material which you don't want
released under that license. Anyone can do this at any time, not just you, so to assist
others, please include a note inside <-- and --> saying that you're the original
author, giving the source page and stating that you've removed it as a copyright
violation. This will help us to know that it was a deliberate change rather than one of
the occasional cases of someone exploiting our open process to vandalise a page. Yes, we
really do let anyone change almost any page at any time."
That addresses his likely concerns, while giving the Wikipedia as much chance as possible
of keeping all useful content. And he just might like the concept and decide to produce a
few pages himself...