The war of words between Milan’s La Scala and London’s Royal Opera House ratcheted up considerably over the weekend, with La Scala releasing a raft of correspondence which, it claims, show that conductor Riccardo Muti was not out of line in withdrawing from an ROH production. Meanwhile, the London house has announced that Antonio Pappano has agreed to cancel several U.S. engagements to replace Muti on the podium.