Which Pope Understood the Reformation?

Pope Leo X, 1520: Arise, O Lord, and judge your own cause... A roaring sow of the woods has undertaken to destroy this vineyard, a wild beast wants to devour it... Since these errors, as well as many others, are found in the writings or pamphlets of a certain Martin Luther, we condemn, reject and denounce these pamphlets and all writings and sermons of this Martin, be they in Latin or in other languages, in which one or more of these errors are found. For all times do we want them condemned, rejected and denounced. [source]

 Pope John Paul II, 1983: For the Catholic Church the name of Martin Luther is linked, across the centuries, to the memory of a sad period and particularly to the experience of the origin of deep ecclesiastical divisions. For this reason the 500th anniversary of Martin Luther's birth should be for us a reason to meditate, in truth and Christian charity, on that event fraught with historical significance which was the period of the Reformation. Because time, by separating us from the historical events, often permits them to be understood and represented better. ["Pope John Paul II's Letter on the Fifth Centenary of Birth of Martin Luther" as cited by Gregory Sobolewski.

See also: Pope calls for re-evaluation of works of Luther: "In the first place it is important to continue accurate historical work. It is a question of, through an investigation without taking sides, motivated only by the search for truth, arriving at a just image of the reformer, of the entire epoch of the reformation and of the people who were involved in it." "Guilt, where it exists, must be recognized on whichever side it is found. Where polemics have clouded the view, the direction of this view must be corrected and independently by one side or the other."

It's interesting to me that Roman Catholic laymen (well, at least those zealous for their Romanism) typically gravitate toward the view of Pope Leo X. That is, the new strain of self-proclaimed Internet apologists that fill places like the Catholic Answers forums, typically fight for the cause of Pope Leo. This recent Catholic Answers thread though is interesting because it demonstrates both views are alive within Romanism. Roman Catholics appear to have a wide berth on how to understand the Reformation.

For further reading, see: Gregory Sobolewski, Martin Luther: Roman Catholic Prophet. This is probably the most extensive current study on the Roman Catholic understanding of Luther in English.