Hungary’s sickly and frivolous King Louis II, on ascending to the thrones of Hungary and Bohemia, had been adopted by Holy Roman Emperor Maximilian I.
When Maximilian died in 1519, Louis had been raised by his legal guardian, his cousin George of Brandenburg.
Louis is declared of age in 1521, but remains under control of the Hungarian magnates.
At the Hungarian court there are two parties arrayed against each other: the Magyar party under the leadership of John Zápolya, Voivode of Transylvania, and the German party under the leadership of George of Brandenburg, whose authority has been increased by the acquisition of the duchies of Ratibor and Oppeln by hereditary treaties with their respective dukes and of the territories of Oderberg, Beuthen, and Tarnowitz as pledges from the king, who cannot redeem his debts.
George makes made an arrangement with Petar Keglević, who is captain of Jajce, in 1521 and pulls back from Hungary and Croatia; this arrangement, which will be accepted by Louis II in 1526, will not be not accepted by Holy Roman Emperor Ferdinand I until 1559.
The Hungarians have long opposed Ottoman expansion in southeastern Europe, but the fall of Nándorfehérvár (present-day Belgrade, Serbia) and Szabács (now Šabac, Serbia) in 1521 means that most of southern Hungary is left indefensible.
The strongest nobles are so busy oppressing the peasants and quarreling with the gentry class in the parliament that they fail to heed the agonized calls of King Louis against the Turks.