Dear Sridhar Sorry for the late response. The writing direction had been varied all over the world. Most Semitic languages were and are written from right to left, like Aramic which can be taken as the main source of inspiration for scripts of this region. Even Greek in the early stages was written that way. Kharoshti, the script that was used in the Indian subcontinant from the 3rd century Bc till about 4th century AD was written from right to left. some of the Ashokan inscriptions are in this script.
Greek then came written in what is called 'boustrophedon' way. The word is from Greek for ox-turning. In this the writing proceeds in one direction in one line (such as from left to right) and then in the reverse direction in the next line (such as from right to left). The term derives from the way one would plow land with an ox, turning the ox back in the other direction at the end of a row.
For sometime, we understand, Brahmi was written this way, before it came to be written from left to right. I have not found reference to any epigraphic evidence. The Ashokan edicts in Brahmi are from left to right and belong to the 3rd century BC.
Hope I have given some idea on this topic. You are welcome to continue discussion on this subject.
Dear Mr Swaminathan Thank you very much for your reply....It would definitely be very interesting to know about the evolution of written tamil....But my understanding was Tamil if not preceeding Greek was atleast its contemporay...Its surprising that Tamil had inspiration from Greek Thank you once agin for your reply Sridhar
Dear Sridhar Your inference that Greek had influenced is not quite right. Most people make mistake by considering script and language to be the same.
I said that Brahmi was also written the way Greek written in the initial phase. Brahmi script is the mother of Tamil script. If there is a connection between Greek and Tamil, it was in the script, that too indirect.