The Esterházys arose among the minor nobility of the northern part of the Kingdom of Hungary (today's southwest Slovakia), originally a branch of the Salamon clan ("de genere Salamon") by the name "Zerházi" ("de Zerhásház" / "de Zyrház" / "de Zyrhas"). Their first known ancestor was Mokud (Mocud) from the Salamon clan, who was a military serviceman and landowner in the Csallóköz region of Western Hungary (today Žitný ostrov in southwestern Slovakia), and Pristaldus, a judicial office-holder in the court of Béla III of Hungary.