Duke Frederick of Saxony, Grand Master of the Teutonic Order, died in December 1510.
Albert was chosen as his successor early in 1511 in the hope that his relationship to his maternal uncle, Sigismund I the Old, Grand Duke of Lithuania and King of Poland, would facilitate a settlement of the disputes over eastern Prussia, which had been held by the order under Polish suzerainty since the Second Peace of Thorn (1466).

The new Grand Master, aware of his duties to the empire and to the papacy, refused to submit to the crown of Poland.
As war over the order's existence appeared inevitable, Albert made strenuous efforts to secure allies and carried on protracted negotiations with Emperor Maximilian I. The ill-feeling, influenced by the ravages of members of the Order in Poland, culminated in a war which began in December 1519 and devastated Prussia.
Albert was granted a four-year truce early in 1521.

The dispute was referred to Emperor Charles V and other princes, but as no settlement was reached Albert continued his efforts to obtain help in view of a renewal of the war.
For this purpose he visited the Diet of Nuremberg in 1522, where he made the acquaintance of the Reformer Andreas Osiander, by whose influence Albert was won over to Protestantism.

The Grand Master then journeyed to Wittenberg, where he was advised by Martin Luther to abandon the rules of his order, to marry, and to convert Prussia into a hereditary duchy for himself.
This proposal, which was understandably appealing to Albert, had already been discussed by some of his relatives; but it was necessary to proceed cautiously, and he assured Pope Adrian VI that he was anxious to reform the order and punish the knights who had adopted Lutheran doctrines.
Luther for his part did not stop at the suggestion, but in order to facilitate the change made special efforts to spread his teaching among the Prussians, while Albert's brother, Margrave George of Brandenburg-Ansbach, laid the scheme before their uncle, Sigismund I the Old of Poland.
Duke Frederick of Saxony, Grand Master of the Teutonic Order, died in December 1510. Albert was chosen as his successor early in 1511 in the hope that his relationship to his maternal uncle, Sigismund I the Old, Grand Duke of Lithuania and King of Poland, would facilitate a settlement of the disputes over eastern Prussia, which had been held by the order under Polish suzerainty since the Second Peace of Thorn (1466).
The new Grand Master, aware of his duties to the empire and to the papacy, refused to submit to the crown of Poland. As war over the order's existence appeared inevitable, Albert made strenuous efforts to secure allies and carried on protracted negotiations with Emperor Maximilian I. The ill-feeling, influenced by the ravages of members of the Order in Poland, culminated in a war which began in December 1519 and devastated Prussia. Albert was granted a four-year truce early in 1521.
The dispute was referred to Emperor Charles V and other princes, but as no settlement was reached Albert continued his efforts to obtain help in view of a renewal of the war. For this purpose he visited the Diet of Nuremberg in 1522, where he made the acquaintance of the Reformer Andreas Osiander, by whose influence Albert was won over to Protestantism.
The Grand Master then journeyed to Wittenberg, where he was advised by Martin Luther to abandon the rules of his order, to marry, and to convert Prussia into a hereditary duchy for himself. This proposal, which was understandably appealing to Albert, had already been discussed by some of his relatives; but it was necessary to proceed cautiously, and he assured Pope Adrian VI that he was anxious to reform the order and punish the knights who had adopted Lutheran doctrines. Luther for his part did not stop at the suggestion, but in order to facilitate the change made special efforts to spread his teaching among the Prussians, while Albert's brother, Margrave George of Brandenburg-Ansbach, laid the scheme before their uncle, Sigismund I the Old of Poland.
Albert, Duke of Prussia