The siege of Székesfehérvár also known as the siege of Stuhlweissenburg (French: Prise d'Albe-Royale, German: Belagerung von Stuhlweißenburg, Turkish: İstolni Belgrad) began on 4 September 1601 when an Imperial force sent by Holy Roman emperor Rudolf II, under the command of Frenchman Philippe Emmanuel de Lorraine, duc de Mercoeur, besieged the Hungarian fortress of Székesfehérvár occupied by the Ottomans since 1543.

[2] In 1600 Frenchman from the Duchy of Lorraine, Philippe-Emmanuel, duke de Mercoeur,[a] who had volunteered to serve with the army of the Holy Roman against the Turks in Hungary, was called by Rudolf II to become Commander-in-chief of the Imperial troops.

[3] In March 1601 the Ottoman Sultan sent an official complaint to King Henry IV of France to protest about the presence of a Frenchman in command of the Habsburg army.

[3] In September 1601 an army under Mercoeur and Habsburg commander Count Adolf von Schwarzenberg was sent by Rudolf II to lay siege to Stuhlweißenburg (as Székesfehérvár was known in German).

Mercoeur promptly launched an attack "with great noise" bringing the bulk of the Ottoman defenders towards the front of the fortress while Russwurm, according to the established plan, scaled the walls with his men and seized the city.