The political situation of the Holy Roman Empire of the German Nation had been in a state of decay since the 15th century.
Threats from OutsideIn the northeast, was the state of the Teutonic Order which was bound by allegiance to the Polish King, but was also tied with the German Emperor. This led to conflicts which resulted in parts of the state of the Teutonic Order being subjugated to Poland.
The homogeneity of Europe was destroyed through the strong nationalistic efforts of the different territories. Above all, France and Spain became strong autonomous nations. The foreign policy conflict of Emperor Karl V with France during the first decade of the Protestant Reformation weakened the power of the emperor's domestic policy and gave the Reformation the chance to take hold.
The same was true for the conflict with the growing Turkish empire. Constantinople's fall in 1453 is only one example of the extraordiary growth in the strength of the Turks.
After numerous successful conquests in Asia Minor, the Turkish empire expanded westward. The area of the lower Danube river (today Hungary) and large parts of the countries along the Mediterranean and North Africa were already captured or used as a buffer zone between the Turkish and Habsburger Emperors.
The Inner Weakness
Lastly, the changing domestic situation can be added to the picture of the crisis-ridden empire. The unity of the Holy Roman Empire disintegrated after the centuries-long conflicts between popes and emperors. Domestic policy, now lay more in the hands of the Emperor, but now the princes were demanding more and more control as well.
Imperial Reforms of MaximilianKaiser Maximilian tried to stop the fall of the Empire. The first culmination point was the organisation of an Imperial government in the year 1500, which was made up of 20 Imperial politicians. In this 'State Council' the emperor was the chairperson; two deputies were from the Imperial Court and 17 representatives came from the princes and people of social rank. Because these reforms were begun during the reign of Emperor Maximilian I (1493 - 1519), he has gone down in history as the last true knight of the German emperors and as the patron of Humanists.
The Edict of WormsThe power struggles continued between the emperor and princes. This was made clear in 1521 by the fact that the emperor (now Emperor Karl V) had the right to impose edicts. Take for example, the Edict of Worms, which banned Luther from the Empire and declared him an outlaw wanted dead or alive, anyone could kill him without threat of prosecution. See also: Luther at the Imperial Diet of Worms
The implementation of this edict, which also tried to prevent any form of expansion of the Reformation, depended upon the consent of the princes. The Edict of Worms had to be executed by the Imperial Regiment, and since this did not happen, it got pushed from Imperial Diet to Imperial Diet and finally at the Imperial Diet in Spires (German: Speyer) it was decided to grant the enforcement of the edict to the sovereigns.
So, a space emerged in which the historical and theological phenomenon we call the Reformation could spread; the Reformation would survive.