After Frederick III, Elector of Saxony concealed Luther at the Wartburg (1521–1522), Karlstadt and Thomas Müntzer started the first iconoclastic movement in Wittenberg and preached theology that was viewed[by whom?]

Despite coming closer to the Reformed tradition by the time of his death, Karlstadt maintained his own distinct understanding on many theological issues throughout much of his life.

From 1515–16, he studied in Rome, where he obtained the double degree in canon and civil law (utriusque juris) at the Sapienza university.

[2] Electors of Saxony Holy Roman Emperors Building Literature Theater Liturgies Hymnals Monuments Calendrical commemoration Before 1515, Karlstadt was a proponent of a modified scholasticism.

His beliefs were challenged during his stay in Rome, where he alleges he saw large-scale corruption in the Catholic Church, and on a document dated 16 September 1516 he wrote a series of 151 theses.

[2] On 15 June 1520 Pope Leo X issued the papal bull Exsurge Domine that threatened Luther and Karlstadt with excommunication, and condemned several of their theses.

He did not elevate the elements of communion, wore secular clothing during the service, and purged all references to sacrifice from the traditional Mass.

In January 1522, the Wittenberg city council authorized the removal of imagery from churches and affirmed the changes introduced by Karlstadt on Christmas.

Frederick let most of the Mass revert to its Catholic form, but in a letter to the Wittenberg Council, he noted his personal compassion for Karlstadt.

Karlstadt reasserted some of his moderately mystical leanings, continued wearing peasants' clothing, asked to be called "Brother Andreas," and became disillusioned with academic life.

In July, Luther published the Letter to the Saxon Princes, in which he argued that Thomas Müntzer and Karlstadt agreed, and were both dangerous sectarians with revolutionary tendencies.

This led to the well-known confrontation at the Black Bear Inn in a conversation recorded by a Martin Reinhardt and published within a month.

Erasmus described in a letter of 1529 such a riot that had occurred in Basel: They heaped such insults on the images of the saints, and the crucifix itself, that it is quite surprising there was no miracle.

Special aim was taken at Marian pictures visited in pilgrimages, but he also called for the removal of all public religious imagery and symbols.

The Seventeen Provinces (now the Netherlands and Belgium and parts of northern France) were hit by a large wave of Protestant iconoclasm in the summer of 1566.

The "Beeldenstorm" is often held to mark the start of the Dutch Revolt against the Habsburg rulers of the Netherlands, although the fighting did not begin in earnest for some years.

His books on the Lord's Supper were published with the co-operation of the Swiss Brethren in Zürich, specifically Felix Mantz and probably Andreas Castelberg, as well as Karlstadt's brother-in-law, Gerhard Westerburg of Cologne, who baptized over 2,000 adults in his swimming pool.

Karlstadt's influence on Protestantism in general included the abolition of mandatory celibacy (he married more than three years before Luther, and published several writings on the subject, both in Latin and German).

[13] In Amsterdam, the founders of the English Baptists, John Smyth and Thomas Helwys, accepted central teachings from the Waterlander Mennonites.