The political organisation, as it was established by the first Mithradates, was accordingly in substance that of the Achaemenids. The family of the founder of the dynasty is invested with all the lustre and with all the consecration of ancestral and divinely-ordained rule; his name is transferred _de jure_ to each of his successors and divine honour is assigned to him; his successors are therefore called sons of God,[3] and besides brothers of the sun-god and the moon-goddess, like the Shah of Persia still at the present day; to shed the blood of a member of the royal family even by mere accident is a sacrilege--all of them regulations, which with few abatements recur among the Roman Caesars, and are perhaps borrowed in part from those of the older great-monarchy. [Sidenote: Megistanes.] Although the royal dignity was thus firmly attached to the family, there yet subsisted a certain choice as to the king. As the new ruler had to belong as well to the college of the “kinsmen of the royal house” as to the council of priests, in order to be able to ascend the throne, an act must have taken place, whereby, it may be presumed, these same colleges themselves acknowledged the new ruler.[4] By the “kinsmen” are doubtless to be understood not merely the Arsacids themselves, but the “seven houses” of the Achaemenid organisation, princely families, to which according to that arrangement equality of rank and free access to the great-king belonged, and which must have had similar privileges under the Arsacids.[5] These families were at the same time holders of hereditary crown offices,[6] _e.g._ the Surên--the name is like the name Arsaces, a designation at once of person and of office--the second family after the royal house, as crown-masters, placed on each occasion the tiara on the head of the new Arsaces. But as the Arsacids themselves belonged to the Parthian province, so the Surên were at home in Sacastane (Seistân) and perhaps Sacae, thus Scythians; the Carên likewise descended from western Media, while the highest aristocracy under the Achaemenids was purely Persian. [Sidenote: Satraps.]