Johann Rudolf Stadler (1605 – 16 October 1637) was a Swiss Protestant clockmaker. He is mostly known for his life in Safavid Iran, where he worked as a prosperous watchmaker. He eventually fell victim to intrigue in relation to the death of a trespasser on his property, and was executed.

A native of Zürich, Stadler was a son of a certain Erhard, a seller of stoves.^[1][2] In 1627, he left on a mission to Constantinople, the capital of the Ottoman Empire, for his uncle Johann Rudolf Schmid von Schwarzenhorn.^[1][2] There, he met the French traveller Jean-Baptiste Tavernier.^[1] Stadler and Tavernier subsequently travelled together to Isfahan, the capital of the Safavid Empire.^[1]

Stadler arrived in Safavid Iran in 1631 where he soon made a name for himself as watchmaker.^[1][3] Safavid Shah ("King") Safi (r. 1629–1642) was pleased by the watch that Stadler made for him while at Isfahan, and he was subsequently employed at court.^[3] Over the next three years, Stadler repaired all of the Shah's broken watches.^[1][3] Stadler became a wealthy man of high standing in the Safavid Empire, and married a Nestorian woman.^[1] In 1637, he sought to return to Europe together with the Holstein embassy which was led by Otto Bruggeman, his brother-in-law. Shah Safi however offered him a large amount of money to stay.^[3]

Before Stadler was able to make a decision, however, he shot dead a man who had broken into his house at night.^[3] Stadler had caught the same intruder once before and had ordered him never to set foot again in his house.^[1] According to Tavernier, the man was not a burglar, but the lover of Stadler's wife.^[3] Though Safavid law was on Stadler's side, intrigue sealed his fate; the Safavid court had him incarcerated and sentenced to death.^[1] Shah Safi was willing to pardon Stadler if he converted to Islam and had himself circumcised; however, as he refused, the court carried out the sentence. He was executed by the sword, on 16 October 1637, and was buried in Isfahan.^[4]

• Floor, Willem (1992). "Clocks". In Yarshater, Ehsan (ed.). Encyclopædia Iranica, Volume V/7: Class system V–Clothing X. London and New York: Routledge & Kegan Paul. pp. 713–718. ISBN 978-0-939214-75-4.
• Lassner, Martin (18 July 2011). "Johann Rudolf Stadler". Dictionnaire historique de la Suisse (DHS) (in French). Retrieved 13 April 2020.
• Matthee, Rudolph (2013). "Iran's Relations with Europe in the Safavid Period: Diplomats, Missionaries, Merchants and Travel". In Langer, Axel (ed.). The Fascination of Persia – Persian European Dialogue in Seventeenth-Century Art and Contemporary Art of Teheran. Zürich: Scheidegger und Spies.
• Rota, Giorgio (2017). "Conversion to Islam (and sometimes a return to Christianity) in Safavid Persia in the sixteenth and seventeenth centuries". In Norton, Claire (ed.). Conversion and Islam in the Early Modern Mediterranean: The Lure of the Other. Routledge. ISBN 978-1317159797.