The Kusana Invasion of India under Kumaragupta

Summary

Buddha Prakash examines whether the Kusānas, tribal rulers of the north‑western frontier, invaded the Gupta empire during the reign of Kumaragupta I. The Kusānas were a constant menace to the fertile Gangetic plains, yet Chinese records show that by the late 4th century they were counted as one of the four ‘sons of heaven’ separate from India, implying they had lost control of the subcontinent. Earlier, Samudragupta had campaigned to Kashmir; Candragupta II (Vikramāditya) later defeated the Saka or Kushan king, disguised himself as a queen and pursued campaigns to the Oxus. These victories confined the Kusānas to their homeland and ushered in decades of peace. Kumaragupta inherited this stability but toward the end of his long reign the empire weakened, indicated by silver‑plated copper coins and a lack of inscriptions after 448 A.D. Evidence suggests that during this period the Kusānas, influenced by the expansionist Sassanid empire, allied with other north‑western tribes and raided Gupta territory. The paper discusses how the Sassanids subjugated the Kusānas: Persian coins label crown princes Kushānshāh; marriage alliances between Sassanid monarchs and Kushan rulers of Kabul/Punjab are recorded, showing Iranian dominance. As Gupta control faltered, Kushan–Sassanid pressure increased. Kumaragupta responded by seeking alliances along the Silk Road—pilgrims like Fa‑hien and Che‑mong travelled between India and China during this period—and by strengthening defences. The article reviews accounts in Sanskrit dramas and chronicles describing how Candragupta II killed the Saka king, noting disagreements about the battle’s location. Ultimately, Prakash concludes that although the Kusānas never reconquered India, their incursions during Kumaragupta’s reign, reinforced by Sassanid power and tribal migrations, foreshadowed later Hun invasions and expose the vulnerabilities of the late Gupta empire.