A is friends with the mayor's wife." I couldn't believe my eyes. In fact, when I went to look up the citation in print to send it to you, it had been changed to "She is a good friend of ... " Did "The World's Greatest Newspaper" get it wrong in the first place, or did it fix something that wasn't broken?
For purposes of looking into word histories, surely the Oxford English Dictionary is the World's Greatest Dictionary, and it contains citations for forms of be friends with that date back as far as Shakespeare: "I am good Friends with my Father" is in Henry IV. The revised edition of the OED, now in progress, will have a lot more on this issue; unfortunately, the new scholarship about friend that Oxford's lexicographers have been amassing won't be publicly available for quite a while.
Starting next month the first sliver of the OED's updated text, consisting of about 800 revised entries and 200 new ones, will be published online (at www.oed.com), together with all the 298,000 other entries in the current edition. From then on, four times a year another sliver of updated text will appear, until the revised edition is complete, supposedly in 2010.
I asked the dictionary's principal philologist, Edmund Weiner, if he had anything to share in advance about the quirky be friends with idiom. Usage, he explained, seems in the sixteenth century to have slipped from make [someone] a friend to such less logical constructions as hold friends with, make friends to, and be friends with. By now most of these except make friends with and be friends with have dropped out of use. The revised edition will demonstrate the progression in some detail, Weiner avers, though the OED has yet to array all the evidence, because the deadline for communicating it to the OED's readership isn't exactly pressing.