According to IBDB, The original production of Once Upon a Mattress moved theatres FIVE times between 5/59 and 6/60. Why?
May 1959 - Jul 2, 1960 Musical / Original Phoenix Theatre, NY, USA Alvin Theatre, NY, USA Winter Garden Theatre, NY, USA Cort Theatre, NY, USA St. James Theatre, NY, USA
Their subscription at the Phoenix ran out unexpectedly as theatre managment underestimated the popularity of the new show, but the cast held a mock strike to find a new house, and then the Alvin became available. Mattress then replaced the flop Greenwillow at the Winter Garden until West Side Story returned from tour at kicked them into the Cort until room became available at the larger St. James Theatre.
The show actually used the line "the most moving musical in town" in their ads.