Did Castana start the Saka era

Summary

The origin of the Śaka Era (78 AD) has long been a debated issue in Indian historiography, with various scholars proposing different founders. Early theories suggested that rulers like Vonones, Nahapāna, or even the Kuṣāṇa king Kaniṣka were responsible, but each theory faced serious limitations. Vonones was a Parthian, not a Śaka; Nahapāna was defeated by Gautamīputra Śātakarṇi and had no lasting era; and Kaniṣka, though powerful, was not of Śaka origin, and no direct evidence links him to the founding of the era. The theory that Cāṣṭana, a Western Kṣatrapa and of Śaka origin, started the era is increasingly considered the most plausible. His dynasty used the era, his independence from the Kuṣāṇas is now recognized, and his coins and inscriptions show no imitation of Kuṣāṇa style. Recent inscriptions also date his reign to around 78 AD, supporting the idea that he initiated the era to commemorate his victories and establish a legacy. Thus, based on ethnicity, chronology, independence, and inscriptional evidence, the theory that Cāṣṭana was the founder of the Śaka Era is seen as the most logical and historically sound.