Archeological finds prove that the Eisenstadt area was already settled in the Hallstatt period. Celts and Romans settled somewhat later. During the Migration Period, the area was settled by different Germanic tribes and the Huns. Around 800, during the reign of Charlemagne, settlement by the Bavarii began.
The fortress built on the original earth works was destroyed by the troops of Leopold III, Margrave of Austria. In 1241, it was destroyed by the Mongol invaders. In 1373, the town came into the possession of the Kanizsai family, who rebuilt the walls surrounding the town and built a fortress at the site of the present day castle between 1388 and 1392. In 1388, Eisenstadt was given the right to hold markets by Emperor Sigismund.
In 1445 Archduke Albert VI of Austria acquired the town. In 1451 it was ceded to Frederick III, Holy Roman Emperor by Matthias Corvinus in return for the Holy Crown of Hungary. Matthias Corvinus reconquered it by force in 1482, but Maximilian I acquired it again in 1490. It remained under Habsburg rule until 1622. In 1529 and 1532 the Ottoman Empire conquered Eisenstadt with their advance on the city of Vienna (see Ottoman wars in Europe). It was captured by the army of Imre Thököly in 1683, and it saw the defeat of the kuruc army of Sándor Károlyi by the Habsburgs in 1704. A royal town since 1648, it was destroyed by fire in 1589 and 1776.
In 1648, it passed under the rule of the Esterházy family. These Hungarian princes permanently changed the face of the city due to their extensive construction especially on their castle, Schloss Esterházy. The appointment of Joseph Haydn as the prince's Hofkapellmeister (court orchestra director, composing and performing music) began the great artistic period in the city's history. In 1809, Eisenstadt was occupied by French troops during the Napoleonic Wars; in 1897, it was joined to the railway network.
Until the end of World War I, it was the seat of Kismarton
