That’s a very interesting assumption, Revilod. Röntgen was in March 1930 still in Edinburgh when he received a message from Dr Curt Rudolf Mengelberg, director of the Concertgebouw Orchestra and a second cousin of conductor Willem Mengelberg. Röntgen was offered a celebration in honour of his 75th birthday (9 May) and honorary degree at Edinburgh (27 March), to be held in the Concertgebouw on 10 April.
Willem Mengelberg wanted to conduct a piano concerto composed by Röntgen, but then Röntgen should send Mengelberg immediately a complete score. Mengelberg wanted a beautiful, grand concert. And now it comes, Revilod. Röntgen send his two short PCs 6&7, one and a half week earlier premiered at Edinburgh. Mengelberg wanted another work, but Röntgen made a firm stand because he said that the two concertos form a unit (see my earlier post and quote). Mengelberg agreed…
(Gaudeamus, p.269-270).