"Shapur also built a city in Kashkar [喀什, in, Tarim Basin of modern Xingyang, China], which he called Hasar Shapur and settled with Easterners. This is the story of its construction:
When Shapur went to Persia, he crossed the Kashkar desert and met an old man gathering wood. The king disguised himself and went to ask him about his country and family. He also asked him if it were possible to build a city there. The old man replied: 'If I can learn to write despite my advanced age, you can build a city here.' The king ordered the old man to be entrusted to teachers to carefully instruct him in the religion of the Magi and fire-worshippers [Zoroastrians] until he returned from Istakhr. The old man learned to write and the city was built."

—The Chronicle of Seert, tr. by Anthony Alcock, 2014: 6.

پارسی: "هیچ اثری جز جهالت، سفاهت، تخریب مملکت و عدم تربیت نوکر و رعیت یادگاری نگذارد، و ایران را طوری ویران کرد که اصلاحش از حیز امکان بیرون و سفاهت را به نوعی و درجه‌ای اعلی رسانید که زبان از تقریر و قلم از تحریر و وصف عاجز باشد."

Translation: "He has left no result but idiocy, foolishness, destruction of the country and not educating the people as a remainder of himself, and he so ruined Iran that its restoration is utterly impossible and gave stupidity such a high seat that cannot be put into words and pens cannot write and describe."

—Abbas Mirza Molk Ara (1839-1897 AD), on the effects of the governance of his brother Naser al-Din Shah Qajar, the fourth ruler of the Qajar dynasty.

"It is to be supposed that Ardashir’s claims to the Arsacid throne were treated by the most powerful Parthian clans of the East as legitimate demands, for the prince was actually an Arsacid through his father’s line. The rebellion led by Ardashir was just another phase of a long-lived conflict between the Younger Arsacids and the Indo-Parthian rulers, who stemmed from the Sinatrucid line. Ardashir’s rebellion against Artabanus IV would have had no chance of success without Ardashir’s claim to Arsacid descent."

—Marek J. Olbrycht, Polish historian and archeologist.

"Dynastic Connections in the Arsacid Empire and the Origins of the House of Sāsān", by M. J. Olbrycht,
in "The Parthian and Early Sasanian Empires: Adaptation and Expansion", Oxford (2016), ed. V. S. Curtis, E. Pendleton, M. Alram, T. Daryaee.

"The Magi and in general the entire Iranian/Aryan race (άρειον γένος), as Eudemus [of Rhodes] also writes, call the whole of that which is intelligible and that which is unified (= being) in some cases Time, in others Place; from this comes by discrimination either a good god and an evil demon, or light and darkness before these, as some say. Then they also posit, after the undifferentiated nature, the double series of higher beings, of which Ohrmazd (᾽Ωρομάσδη) reigns over the one and Ahriman (᾽Αρειμάνιον) over the other."

—Damascius (458-538 AD), "Difficulties and Solutions of First Principles".

"We examined the customs of our forebears, but, concerned with the discovery of the truth, we [also] studied the customs and conducts of the Romans and Indians and accepted those among them which seemed reasonable and praiseworthy, not merely likeable. We have not rejected anyone's teachings because they belonged to a different religion or people. And having examined the good customs and laws of our ancestors as well as those of the foreigners, we have not declined to adopt anything which was good nor to avoid anything which was bad; And affection for our ancestors did not lead us to accept customs which were not good."

—Shahanshah Khosrow II Anushirwan, excerpt from "Kārnāmag ī Husrav Anōšag-ruvān".
Preserved in Arabic translation, "Tajārib al-Umam", by Pur Muskōya (932-1030 AD).

"The Zoroastrians say: 'We force no one to enter into our religion, nor do we encourage them to do so, for it is a religion that God has assigned unto us. Yet we do not prevent those who wish to enter it. We fight and carry the sword to the [other] nations seeking their obedience to our rule and taxation, but wars for religion, we never wage.'"

—Abd al-Jabbār Hamadāni (935-1025 AD), "Tathbīt dalā'il al-nubuwwa", 1:185.

Sassanian royal succession in Iranian sources, pt. 1:

"Of the blights of kingship is the announcement of successors. First harm that comes from it is the enmity between the king and his successor for no hostility is greater than the one between two men trying to overthrow each other's glory. The king never wants the successor to achieve his higher degree with his own death, and likewise the successor doesn't wish the king a long life, thus the happiness of both lies in the other's death.

If the two are distanced by the slanderous, each will gather allies destroy the other, and at the end of this conflict the victorious side will be furious and think of some as their enemy, demoting and jailing them, evoking further conflict and leading to future wars, which is why I fear for future kings...

[contd.] The king of kings must first consider the choice of god, then the people, and then himself, then choose a successor and write his name in four identical letters, seal them and entrust them to four grandees, and from then on must be extremely cautious of his actions and sayings, so not to arise suspicion over who is the chosen successor. When the king passes away, the four letters must be opened and read, and the successor whose name is read must be crowned as the new king of kings."

—Covenant of Ardashir (Pers. *ēvēn ī ardašīr, Ar. aḥd-i ardašīr).
Preserved in Arabic translation in: 1-"Tajārib al-Umam", by Pur Muskōya and 2-"Naṯr al-Durar fi al-Muhāḍirāt" by Abu Saad Avi.

Sassanian royal succession in Iranian sources, pt. 2:

"Another question you have asked: 'What has prevented the king of kings from deciding and naming a successor?'
The answer is: He worries that if he announces a successor, they will be suspicious of everyone thereafter, so if someone distances himself from his affinity, grudges will be taken; And also when the king sees the successor, he might think: "He impatiently awaits my death," and thus their friendship and union will break."

—The Letter of Tosar (Tansar) to Goshnasp ca. 3rd century AD.

Old Persian: "imam apadānam vašnā Auramazdā, Anăhită utā Mitra akunām Auramazdā Anăhită utā Mitra mām pāntuv hacā vispā gastā utā imam taya akunām mā vijanāntiy mā vināθayāntiy."

Translation: "by the greatness of Ahuramazda, Anahita and Mithra I built this Apadana. May Ahuramazda, Anahita and Mithra protect me from all evil, and never harm or damage what I have built."

—Inscription A2Ha, by the Achaemenid Shahanshah Ardashir II (Artaxšaça/Artaxerxes), housed in the British Museum (M. N. 90854)

"Aršāma And His World - The Bodleian Letters In Context", in three volumes, edited by Christopher J. Tulpin & John Ma, Oxford University Press (2020).
Translation, commentary and research on the letters and bullae of Aršāma, the Achaemenid satrap of Egypt in 5th century BC.

Effectively groundbreaking set of research on Achaemenid history and culture, set to give a much better vision of Iranian administration in the Achaemenid period.

—Download from Internet Archive (archive.org) all three volumes in PDF:
🔗 Link

Pārsīg: "(ped dēn gōbed) ēn-z kū ahlavān fravahr az pas ī xvēš yazišn ud āfrīn ī mardān ī ahlavān xvāhend nē šīvan ud mōy."

Translation: "It says in the dēn (=Avesta) as well, that the 'fravahr's of the righteous ones who have passed away want after themselves the prayers and blessings of righteous people, not tears and shrieking."

—Dēnkird, Book IX, M 799; (on the lost) Stūdgar Nask, 11.

"Razes believed that five things are pre-eternal and have existed forever; Namely: 1- God the creator, 2- Soul, 3- Matter, 4- Space, 5- Time.
Some believe that Razes adopted this idea from the Carrhaeans, while the truth is that this concept became popular between them after him.
Biruni (973-1048 AD) has said that Razes adopted it from the Greeks. The truest notion we find in the 'Kitāb al-fiṣal fī l-milal wa-l-ahwāʾ wa-l-niḥal' of Ibn Hazm of Andalusia (994-1064 AD): "The Magians believe that the Creator, that is Ohrmazd; Satan, that is Ahrmen; Gāh, that is Time; Jāy, that is Place; and Hyle or Matter, that is Substance, are pre-eternal."
As Mas'udi (896-956 AD) gives the very same account in 'Kitāb al-Tanbīh wa l-ishrāf', it can be said that Razes was under the influence of ancient Iranian philosophy."

—'History of Iranian Philosophers', by Ali Asghar Halabi.

"… those scholars who make so much fuss about the all-importance of Parsi tradition, adhere to it only in minor points, such as the meanings of certain words, but abandon it altogether as regards the most important questions, such as the age of Zoroaster, the composition and preservation of the sacred books, the age of the Pahlavi (/Pārsīg=Middle Persian) language etc. Instead of paying, in this respect, the slightest attention to the traditional reports, they maintain, that, for instance, the Zand-alphabet is of Post-Christian origin, and that the Zand-Avesta, as we possess it now, was not written before the time of the Sasanidæ, and had been preserved for many centuries exclusively by memory, opinions which are laughed at and ridiculed by every Parsi priest (and I think justly) as absurdities."

—German orientalist Martin Haug, "An Old Zand-Pahlavi Glossary", Introductory remarks, edited by Hoshegji Jamaspji, Bombay, 1867, XIII-XIV.