Ardashir I (died 242 CE) was the founder of the Sassanid Empire, is ruler of Istakhr (since 206?

), subsequently Fars Province (since 208?

), and finally "King of Kings of Sassanid Empire" (after 226) with the overthrow of the Parthian Empire.

The dynasty founded by Ardashir is to rule for four centuries, until it is overthrown by the Rashidun Caliphate in 651.

Ardashir ("Who has the Divine Order as his Kingdom") is also known as Ardeshīr-i Pāpagān "Ardashir, son of Pāpağ", and other variants of his name include Latinized Artaxares and Artaxerxes.