Time Magazine is home to a colorful, if brief, story about a Philadelphia publishing house taking over a New York outfit—in 1941. The Philadelphia firm, J.B. Lippincott, has an interesting past (one of its previous presidents married the daughter of the man who founded the Wharton School of Business) and survives to this day, as Lippincott, Williams and Wilkins.
It looks like this "sixth borough" rivalry goes way, way back.



Just an FYI (from a former employee), LWW is now owned by the multinational WoltersKluwer although it still uses the LWW imprint. However, the history of the company in Philadelphia is extraordinary.
Thanks for the clarification, Season.