He lost the two days' battle of Kossovo (October 17th-19th) owing to the treachery of Dan, hospodar of Wallachia, and of his old enemy Brankovic, who imprisoned him for a time in the dungeons of the fortress of Semendria; but he was ransomed by the Magyars, and, after composing his differences with his powerful and jealous enemies in Hungary, led a punitive expedition against the Servian prince, who was compelled to accept most humiliating terms of peace.
Many condemnations followed, and hundreds of politicals were immured in hideous dungeons, a state of things which provoked Gladstones famous letters to Lord Aberdeen, in which Bourbon rule was branded for all time as the negation of God erected into a system of government.
The death sentences were, however, commuted to imprisonment for life, and Settembrini was sent to the dungeons of San Stefano.
At a subsequent confederation, held at Lublin in June, Zebrzydowski was reinforced by another great nobleman, Stanislaus Stadnicki, called the Devil, who "had more crimes on his conscience than hairs on his head," and was in the habit of cropping the ears and noses of small squires and chaining his serfs to the walls of his underground dungeons for months at a time.
In consequence of his professed attachment to the doctrines of Luther he was first imprisoned in the dungeons of Antvorskov and thence transferred, in the spring of 1525, to the Grey Friars' cloister at Viborg in Jutland, where he preached from his prison to the people assembled outside, till his prior, whom he won over to his views, permitted him to use the pulpit of the priory church.