Gajabahu synchronism is the chronological device used by historians to help date early Tamil history. The synchronism, first propounded by V. Kanakasabhai Pillai in 1904 in his "The Tamils Eighteen Hundred Years ago" was adopted by some scholars of the time to date Tamil literature.  Kamil Zvelebil, even while acknowledging the fragility of the synchronism, called it the "sheet anchor" of the dating of Tamil literature. The synchronism however, involves numerous conjectures and has been dismissed by Gananath Obeyesekere in his The Cult of the Goddess Pattini (1984) as ahistorical and invalid.