Most classical scholars have conceded that the works of the poet known to us as Homer, are not those of a single individual, but are really the final written form of a long-standing oral tradition. That is, the poems were passed on in spoken form for many years before they were committed to writing. Some of these contain details from historical events (the fall of Troy) which occurred 1500 years earlier. If this seems incredible, consider the example of the Australian Aborigines, who can recite songs which may have been first sung 40,000 or more years ago. Similar thinking may need to be applied to the works of other great thinkers of Classical times. It is possible that the works of Euclid say, are the result of long accumulation, rather than of sudden inspiration. With this in mind, it is possible to conclude that things known to slightly later mathematicians were also known in earlier times.

The mathematician Ptolemy of Alexandria, (2nd century AD) knew some surprising things.....in the Almagest he gives us accurate figures for the size of the earth and its speed of rotation (or more exactly, the speed of rotation of the heavens). Ptolemy tells us that he derived these figures by measuring the shadow cast by a stick in Alexandria and comparing it with that cast by a similar stick in another location hundreds of miles distant, at the same time. Ptolemy does not mention how he was able to communicate instantly over this distance, so it must have been for him a routine matter. The ancients did in fact possess such a system, which consisted of a chain of hilltop stations where large mirrors were positioned. All that is necessary for this arrangement to function as a communication system is a code, and that code is likely to have been the alphabet we have found from Ireland to North Africa.......chalcidic Greek.

And what did they signal each other about, on this  Internet of the Ancients?