Throughout his career Nat Cole was always eager to try new things; even when he had perfected the King Cole Trio into one of the greatest jazz ensembles of all time, he was never content to let anything become formulaic. He got an indication of where his future would lie with his enormous unprecedented success with two new ballads, “For Sentimental Reasons” and “The Christmas Song.” He also made his formal concert hall debut at this time, in theaters and also classical music venues, including Carnegie Hall. By the end of 1947, changes in both his professional and personal lives meant that his first wife, Nadine Robinson, and his musical partner, Oscar Moore, were out of his life.