Two of the great pioneering geniuses of jazz are united on this epochal record, created from sessions cut in April 1961 when Duke Ellington sat in as pianist with Louis Armstrong’s All-Stars, a touring band which Louis took with him all over the world.

I was discussing a lifelong love of jazz with Pedro, a Chilean friend, a comrade who had been a militant during the Popular Unity years and later a socialist prisoner in Pinochet’s prisons who had managed to find refuge in Britain with the support of Sheffield trade unionists in the mid ’70s.

Yes, he said, he had heard of Armstrong and his All-Stars in his home city of Valparaiso as a boy, and the vibrancy of his sound had never left him.