The first date absolutely fixed is that of the coronation of Sahasa Malla in A.D. 1200. The reigns of previous kings as far back as Vijaya Bahu I. can be dated correctly within a year; the chronology between Sena I. and the Chola conquest at the beginning of the eleventh century is approximate. Before the accession of Sena I. we have a few synchronisms to help us, and a certain number of dates given in the Buddhist era. These have been given in the text, but little reliance can be placed on them, except for the reign of Devanampiya Tissa. For the sake of convenience I have taken B.C. 247, as given in Geiger's Mahavansa, p. xxxiii, as the date of his first coronation. But this really is independent of any theory as to the date of Buddha's death, and depends on the synchronism with Asoka and ultimately on that with the contemporary Greek kings. There is no genuine trace of the employment of the Buddhist or of any era before the time of Parakrama Bahu I. in the twelfth century; in documents the reckoning is by regnal years, and the dates in the Buddhist era in the Pali and Sinhala books after Devanampiya Tissa are due to computations by the various authors. Such calculations are made by adding up reigns, placed one after the other regardless of co-regencies and civil war. And the lengths of the reigns in the inscriptions do not always tally with the books; thus we find no reign in the period between Manavamma and Sena I. agreeing with that of an Abha Salamevan, an inscription of whose forty-fifth year exists at Polonnaruwa. We have definite evidence of computation in the date 217 years 10 months and 10 days from the Conversion assigned to the foundation of Abhayagiri Vihara by Vatta Gamani. This obviously is based on the length of reigns, which with twenty-two years for Sona and Guttika come to a total of 218; yet the prophecy as to Duttha Gamani's accession when 136 years had passed from the Conversion pre supposes that these two Tamils ruled for twelve years only {Mhv. xxvii. 6,7}. In the absence of any certainty for the period before the Chola conquest I have merely noted the century, giving however, synchronisms where such occur. By this course confusion is not worse confounded by a new chronology as unreliable as the old. The real difficulty in adjustment lies in the period between the reigns of Kassapa I., fixed by a synchronism as about A.D. 527, and the accession of Sena I., about A.D. 819. Aggabodhi II. and Manavamma were contemporaries of the Chalukya king Pulakesin II., and it seems probable that the time between A.D. 527 and the accession of Manavamma was shorter than it appears to be by adding up reigns; it included a series of disputed successions. From the time of Vijaya Bahu I. I have adopted the dates most recently fixed. In the list of Sovereigns before this reign, I have given for convenience the dates adopted by the Mahavansa Editors.
A.I.C. Ancient Inscriptions of Ceylon, E. Muller, 1883. A.R.E. Annual Report of Epigraphy, Southern Circle, Madras Government. A.S. Archaeological Survey of Ceylon, Ceylon Sessional Papers. C.A. Ceylon Antiquary. De Q. De Queyroz, Conqui eta Temporal e Espiritual de Ceylao, Colombo, 1916. Dpv. Dipavamsa, H. Oldenberg, 1879. E.Z. Epigraphia Zeylanica. J.R.A.S. Journal of the Royal Asiatic Society. J.R.A.S., C.B. Journal of the Royal Asiatic Society, Ceylon Branch. Mhv. Mahavansa, L. C. Wijesinha, 1889; W. Geiger, 1912. N.S. Nikaya Sangraha, Colombo, 1908. Puj. Pujavaliya, Colombo, 1913. Raj. Rajavaliya, Colombo, 1900. Saddh. Saddharmaratnakaraya, Colombo, 1912.