Ardashir I (
r. 224–242), the founder of the
Sasanian Empire, introduced the title "
Shahanshah of the
Iranians" (
Middle Persian: ;
Parthian: ''''). Ardashir's immediate successor,
Shapur I (
r. 240/42–270/72) chooses the titles in a precise manner
in the inscription at Ka'ba-ye Zartosht. In that Shapur names four of his Sasanian predecessors with different titles and in "an ascending order of importance" by giving the title (
Xwaday) "the lord" to Sasan, "
the king" to Papag, "King of Kings of Iranians" to Ardashir, and "king of kings of Iranians and
non-Iranians" (
Middle Persian: ;; ) to himself. The title "King of Kings of Iranians and non-Iranians" has also seen on a single silver coin of Shapur I, which indicates that the title was introduced after his victory over Romans and incorporation of non-Iranian lands into the Sasanian realms. The title was later used in coins of all later Sasanian kings.
Yazdegerd I's reign (), marks a shift in the political perspective of the Sasanian Empire, which (originally disposed towards the West) moved to the East. The shift may have been triggered by hostile tribes in eastern Iran. The war with the
Iranian Huns may have reawakened the mythical rivalry between the mythological Iranian
Kayanian rulers and their
Turanian enemies, which is illustrated by Younger
Avestan texts. The title of Ramshahr (peacekeeper in [his] dominion) was added to the traditional "King of Kings of the Iranians and non-Iranians" on Yazdegerd I's coins. In the Middle Persian
heroic poem Ayadgar-i Zariran (
The Testament of Zarer), the title was used by the last Kayanian monarch (
Vishtaspa) and occurs in the 10th-century Zoroastrian
Denkard. Sasanian interest in Kayanian ideology and history would continue until the end of the empire.
Bahram V (), on some rare coins minted in
Pars, used the title of
kirbakkar ("beneficent"). The reign of
Yazdegerd II () marks the start of a new inscription on the Sasanian coins;
mazdēsn bay kay ("The
Mazda-worshipping majesty, the king"), which displays his fondness of the Kayanians, who also used the title of
kay. Under
Peroz I (), the traditional titulature of
šāhānšāh ("
King of Kings") is omitted on his coins, and only the two aspects of
kay Pērōz ("King Peroz") are displayed. However, a seal demonstrates that the traditional titulature was still used, which indicates that coins do not with certainty display the full formal titulature of the Sasanian monarchs. His brother and successor,
Balash (), used the title of
hukay ("the good king").
Kavad I () was the last Sasanian monarch to have
kay inscribed on his coins—the last one issued in 513. The regular obverse inscription on his coins simply has his name; in 504, however, the slogan
abzōn ("may he prosper/increase") was added.
Khosrow II (), during his second reign, added the
ideogram GDH, meaning
xwarrah ("royal splendor") on his coins. He combined this together with the word abzōt ("he has increased"), making the full inscription thus read as: "Khosrow, he has increased the royal splendor" (
Khūsrōkhwarrah abzōt). The title of King of Kings was also restored on his coins. His two successors,
Kavad II () and
Ardashir III (), refrained from using the title, seemingly in order distance themselves from Khosrow II. ==The king==