A 7th-century Coin
This coin does not list ‘Uthman by name, but it was minted during his reign. It follows Sasanian models, with the name Yazdegerd (the last Sasanian king) kept in Pahlavi script. It also includes the inscription “may his kingship increase” in Middle Persian. Along the edge of that side, there’s an Arabic inscription “in the name of God.” The other side shows a fire altar and includes the date and mint (Sijistan).
A 9th-Century Description
This passage is from Ibn Shabba, who wrote a history of Medina in Arabic in the 9th century.
Source, p. 38.
A 13th-century Depiction
This image is from a manuscript of Bal’ami’s 10th-century Persian History, dated to c. 1300. It shows the election of ‘Uthman.