In 1959, on the eve of the Second Vatican Council, [Jaroslav Pelikan] coined another phrase of continuing relevance when he wrote of “the tragic necessity of the Reformation.”
That phrase appeared in a book titled The Riddle of Roman Catholicism, published while Pelikan was still a Lutheran. Much later in his life, in 1998, he was received into the fellowship of the Orthodox Church in America. This decision represented an Eastward tilt in Pelikan’s own spirituality that had been long in the making. But he continued to believe that the great religious upheaval in the Christian West at the dawn of the modern era had involved both the necessity of reform and a division at once scandalous and tragic.
Source: Timothy George - First Things, "The Reformation: A Tragic Necessity", 11 July 2016, https://www.firstthings.com/web-exclusives/2016/07/the-reformation-a-tragic-necessity