The advent of Pius X to the papacy brought two Motu proprio statements on music in quick succession: one establishing the hierarchy of specifically Gregorian chant and Counter-Reformation polyphony (Tra le sollecitudini, 22 November 1903, but released only after Christmas); and a second laying out the terms of a future, and monopoly-free Vatican Edition (Col nostro, 25 April 1904). 1 In between, a decree of 8 January 1904 from the SCR had cemented the terms of the Motu proprio of the previous November, indicating in very general language that Gregorian reform was to replace older practices as quickly as possible. 2 Solesmes responded immediately. By 24 February Desclée had secured new authorization from the SCR for the abbey’s current chant books. All were endorsed as being consistent with the terms of both the 22 November Motu proprio and the 8 January decree, and were formally signed off on 1 March. None of Dom Pothier’s chant books was among them, and neither was the Liber usualis of 1896. Clearly they were obsolete. By contrast, the newly approved books included the Paroissien romain (1903); and the new Liber usualis (1904) also squeaked in. 3 Identical in all but the language of their rubrics and titles, these latter books contained Dom Mocquereau’s rhythmic indications in their most advanced form. From the point of view of the Old/New Solesmes disputes over rhythm, and the asymmetry of political power between Dom Pothier and Dom Mocquereau, it was a breathtaking move.