Geometry in the classical world

[Musivarius]

I'm looking at the patterns that were used to make up geometric mosaics. Work has been done on how the mosaicists would have physically drawn out the guidelines but I want to look into from which source they gained their technical knowledge, the geometry.

I surmise that this knowledge would have been passed down orally in much the same way as it is with the mosaicists in the Arab world now but what source did they have? A search has come up with Euclid's Elements but before I get in too deep I wondered if anyone had any suggestions as where to look first.

I don't want to overcomplicate things but I wonder if they had a certain set of mathmatical/geometrical principles that were in common use amongst all mosaicists? Not just for the laying out of the patterns but also for the different proportions in different sized rooms.

Ta!