Nothing enhances a composer’s prestige like the advocacy of the right star performer. Back in the days of Mozart, Beethoven, Paganini, and Liszt, those two identities often dwelled in a single person. In today’s classical world, that’s seldom the case. Hence the excitement when Iceland’s superstar pianist Víkingur Ólafsson introduced a concerto custom-tailored for him by John Adams in January 2015. This month in Oslo, Ólafsson’s Norwegian counterpart Leif Ove Andsnes premieres another by his prolific countryman Ørjan Matre, author of previous concerti for clarinet, harp, violin, percussion, and trombone. For Matre, we are told, “the soloist is not merely a virtuosic front figure but a driving force and a resource for the orchestra.” Could Beethoven have said it better? —Matthew Gurewitsch