From Persepolis to Ctesiphon: Investigating Continuity in Ancient Iranian Architecture Through the Arch of Ctesiphon

The Arch of Ctesiphon (Taq-e Kasra), situated in present-day Iraq, stands as an iconic testament to Sasanian architectural ingenuity, exemplifying a remarkable continuity of Persian building traditions. Previous studies have mainly focused on symbolic or stylistic interpretations; however, this study employs a rigorous technical and historical approach to re-examine the geometric principles and construction methodologies underpinning the arch. Through digital reconstructions based on field measurements, the analysis reveals that the vault closely adheres to a catenary curve—celebrated for its structural efficiency—and incorporates golden ratios and pentagonal symmetries into its design. Notably, the arch’s dimensions consistently correspond with those used in the Achaemenid Arash, underscoring the continuity of a modular planning system that originated in Persepolitan architectural practices. Additional evidence, including standardised brick dimensions and vestiges of timber reinforcement techniques, further substantiates the idea of a deliberate transmission of technical expertise. These discoveries inform a proposed reconstruction model of the vault’s geometry, explicitly anchored in Achaemenid measurement systems and architectural terminology. Beyond its engineering sophistication, as demonstrated in this study, Taq-e Kasra serves as a vehicle of dynastic symbolism. A comparative analysis of other Sasanian architectural projects reveals that the deliberate fusion of Achaemenid motifs with mathematically derived proportions and traditional construction methods represents not mere imitation but a sophisticated reinterpretation. Consequently, rather than indicating a historical rupture, the monument exemplifies a conscious revival and nuanced adaptation of indigenous architectural traditions within the broader framework of Sasanian imperial ideology—embodying an enduring synthesis of symbolic continuity, structural mastery, and cultural identity throughout Iranian architectural history.

کلیدواژه ها:

Taq-e Kasra ، Sasanian Engineering ، Catenary Geometry ، Continuity in Persian Architecture ، Achaemenid Metrology