International audienceTimber in an archaeological context can be used to establish chronologies, to understand the history of architecture and to reconstruct cultural landscapes and natural vegetation in the past. In this study, we use the xylological identifications and radiocarbon dating results of five timber fragments recently discovered in three palaces or palace-like structures in Fars (SW Iran) dating back to the period of the Sasanian Empire (224-651 CE). We show that Qal'a-ye Dokhtar, a fortified palace to the north of Firuzabad, was constructed during the power transition from the Parthian to the Sasanian period. On the other hand, the so-called Palace of Ardashir I besides Firuzabad, was accomplished after the power takeover by t...