The lineage of the founder of the Sasanian dynasty, Ardashir I (224-241 CE), is one of the most discussed issues in Sasanian historiography. Depending on time, region, and regional ethnic identity, sources tend to give their own version of Ardashir’s ancestry and beginnings. These narratives are occasionally in sharp contrast with one another, and with our more concrete historical evidence. To complicate matters further, epic stories have also found their way into the sources. However, as conflicting and antithetical as these epic narratives might be, they nonetheless convey something about the mindset of those who created them, and even more importantly, about the socio-political environment in which they were written. With regard to the ancestry of the founder of the Sasanian dynasty, one source, the Karnamag-i Ardaxshir-i Pabagan, is of particular importance. Written at the end of the Sasanian period, this mixture of history and legend lends itself to various historical and literary interpretations, and provides considerable data on late Sasanian attitudes. Significantly, it tells us much about the royal identity of the Sasanian dynasty, and how its kings imagined their origins. By taking the Karnamag as a point of departure, in conjunction with other narratives of the founding of the Sasanian dynasty, and by employing methods of literary analysis, the present paper provides a picture of the aforementioned socio-political attitudes and ideals. It draws on the latest historical interpretations of the founding of the Sasanian dynasty, and on new research on the Sasanian royal identity, to demonstrate the intricacies of the text of the Karnamag and the image it conveys.