Edict of Worms

The Edict of Worms was a decree issued on 25 May 1521 by Emperor Charles V, declaring:

For this reason we forbid anyone from this time forward to dare, either by words or by deeds, to receive, defend, sustain, or favour the said Martin Luther. On the contrary, we want him to be apprehended and punished as a notorious heretic, as he deserves, to be brought personally before us, or to be securely guarded until those who have captured him inform us, whereupon we will order the appropriate manner of proceeding against the said Luther. Those who will help in his capture will be rewarded generously for their good work.

The Papal nuncio at the diet, Girolamo Aleandro, drew up and proposed the denunciations of Luther that were embodied in the Edict of Worms, promulgated on 26 May. The Edict declared Luther to be an obstinate heretic and banned the reading or possession of his writings.

It was the culmination of an ongoing struggle between Martin Luther and the Catholic Church over reform, especially concerning the practice of donations for indulgences. However, there were other deeper issues that revolved around both theological concerns:

On a theological level, Luther had challenged the absolute authority of the Pope over the Church by maintaining that the doctrine of indulgences, as authorized and taught by the Pope, was wrong.[7]
Luther maintained that salvation was by faith alone (sola fide) without reference to good works, alms, penance, or the Church's sacraments. Luther maintained that the sacraments were a "means of grace," meaning that while grace was imparted through the Sacraments, the credit for the action belonged to God and not to the individual.[8]

He had also challenged the authority of the Church by maintaining that all doctrines and dogmata of the Church not found in Scripture should be discarded (sola scriptura).
To protect the authority of the Pope and the Church, as well as to maintain the doctrine of indulgences, ecclesiastical officials convinced Charles V that Luther was a threat and persuaded him to authorize his condemnation by the Holy Roman Empire. Luther escaped arrest and remained in seclusion at Wartburg castle for several months where he continued to write and translate the New Testament into German.

https://en.wikipedia.org/wiki/Diet_of_Worms