The Cambridge History of India, Vol. I: Ancient India v1.c3.10

v1.c3.10

The system of chronology, which has been adopted for the periods of Çaka and Kushāṇa rule, needs some explanation. The chronological difficulties connected with the Vikrama era of 58 b.c. and the Çaka era of 78 a.d. are well known; and it is universally admitted that the names which these eras bear were given to them at a later date, and afford no clue to their origin. The view maintained in this work is that the eras in question mark the establishment of the Çaka and Kushāṇa suzerainties. The idea of suzerainty, that is to say, supreme lordship over all the kings of a large region—'the whole earth,' as the poets call it—is deeply rooted in Indian conceptions of government; and the foundation of an era is recognised as one of the attributes of this exalted position. Now there is abundant evidence that the Çaka empire attained its height in the reign of Azes I and the Kushāṇa empire in the reign of Kanishka. It is natural to suppose therefore that such imperial eras must have been established in these reigns, and that their starting point in both cases was the accession of the suzerain.