It was located in the Archduke's Palace at the Ecazi capital. During the events of the Ecazi Revolt, occasioned by the impulsive marriage of the Padishah Emperor Elrood Corrino IX to Habla of Hassika V, Ecaz was the center of the rebellion, and the Ecazis expelled their ruler, Archduke Ferdinand Ecaz. Due to the magnitude of the revolt, Elrood's forces, the terrible Sardaukar, were insufficient to defeat the rebels, and so the Emperor was forced to ask help to the Great Houses of the Landsraad in order to reestablish order in the Empire. Houses Vernius and Atreides sent their armies, commanded by their lords, Earl Dominic Vernius and Duke Paulus Atreides, the ones who, along with the Sardaukar, defeated the rebels and restored Ferdinand Ecaz in his throne.
Years later, when discord arose again between Houses Ecaz and Moritani, Viscount Hundro Moritani treacherously bombarded the Archducal Palace of Ecaz, leaving just ashes of what had been the ancestral Mahagony Throne.