Joachim's neighbor, John Frederick I, Elector of Saxony, forbade the sale of indulgences, because Albert had outbid his candidate for the see of Mainz, but also on principle, being persuaded by his subject Martin Luther.

As the Jagiellon dynasty was Catholic, Joachim II promised Sigismund that he would not make Hedwig change her religious affiliation.

However, Joachim did not explicitly adopt Lutheranism until 1555, to avoid open confrontation with his ally, Emperor Charles V.[dubious – discuss][citation needed] Prior to this, Joachim promulgated a conservative church order that was Lutheran in doctrine, but retained many traditional religious institutions and observances, such as the episcopate, much of the Mass in Latin, religious plays and feast days.

The Jewish advocate Josel von Rosheim, who was also in attendance, pleaded privately with Joachim to allow the Jews to settle in the Brandenburg again.

[3] Joachim not only loved hunting in person, he also spent great sums on live lions, bears, wolves, and other beasts which he made to fight each other.

He commanded an army of Austrian, Hungarian, German, Bohemian, Italian, and Dalmatian troops, but the Elector was not a seasoned warrior and eventually beat a retreat.

In 1569, he paid Sigismund for a deed of enfeoffment which made Joachim and his issue heirs to Ducal Prussia in case of the extinction of the Prussian Hohenzollern line.