The Reformation was a religious movement that broke with the Roman Catholicism and formed the Protestant church.
The start of the Reformation is considered to be 31st October 1517 when Martin Luther nailed his 95 theses against indulgences to the door of the church in Wittenberg. In Denmark, the Reformation was officially implemented in 1536 - in Lübeck it happened 5th June 1530.
The dance of death in Lübeck's Marienkirche is from 1463, i.e. a long time before the Reformation, so Death is very polite towards the pope who has stood in God's stead. The opposite is true for Copenhagen's dance of Death, which is a bit of Reformatory propaganda. Here the pope is abused by Death, after which he confesses that all his ideas are inspired be the Devil.
Ieg haffuer vist megit paa fundit
I have certainly invented much
Another difference is the Catholic and the Protestant view of work as a road to salvation.
The Reformation was also an iconoclasm were many of our frescoes were covered with whitewash. After the Reformation people were preoccupied with God's words instead of pictures, processionals, holy water, relics etc.
This doesn't necessarily mean that all paintings were covered immediately after the Reformation. Most frescoes show scenes from the Old and New Testament and were let alone - quite literally - since they were neglected and left to decay. Once they became too damaged because of lack of maintenance, they were whitewashed - a long time after the Reformation.
Those paintings that were unpopular after the Reformation were the so-called devotional images. If - for instance - you prayed to the picture of the man of sorrows(2) in Brunnby Church, you would get 89.000 years indulgence - i.e. your time in Purgatory would be reduced by 89.000 years! (which indicates that there must be a long time until Judgement Day).
The dance of death in Berlin was probably whitewashed after the Reformation, which in Berlin was introduced in November 1539. After this, the burgers of Berlin forgot that there had ever been a dance of death until the wall was being repaired in 1860.
A common trait between the dance of death and the Reformation is that both are caused by the plague.
First of all Death has always been known as the great equaliser: He took people from all walks of life and when the bones were dug up on the cemetery some years later, it was no longer possible to distinguish between emperor and peasant. Or to quote Shakespeare: "We fat all creatures else to fat us and we fat ourselves for maggots. Your fat king and your lean beggar is but variable service — two dishes but to one table".
The mass death resulted in better conditions for the survivors. Poor smallholders left their meagre plots and took over the abandoned estates. Rich people in the cities found that the price of food and service had gone way up as the number of workers had dwindled. In this way the old feudal system was beginning to fall apart. Death addresses the dancers as Mr Pope and Mr Emperor. No more "Your Exalted Eminence" or "Your Most Imperial Majesty".
Secondly, the dances of death are always written in the vernacular. The church preached in Latin, but this was getting impossible as most of the learned people had died.
Footnotes: (1) (2)
"To bind" means to make unlawful, and "to loose" means to make lawful. The pope is a successor of Peter the Apostle, so what it means, in effect, is that whatsoever rules the pope maketh up shall receive the Divine rubberstamp of instant approval.