Download Egypt By Cain HOT!
Isadora Rimbey
It may or may not be a two-stage process. The transfer from Jubal (Greek Josephus, Ioubalos; Latin Josephus, Tubal) the musician to his half-brother Tubal (Greek Josephus, Ioubelos; latin Josephus, Tubalcain) the metalworker should be the easy bit- even if the correct distinction between Jubal and Tubalcain was made, the latter makes more sense than his brother as a maker of physical structures.
For the bigger problem, we're probably looking for one pre-11th-century source which treats Josephus' notes on the progeny of Cain and of Seth as a single story about the development of culture (agriculture, music and metalworking from the former; astronomy from the latter) and the preservation of culture through carved writing. If that exists, then Petrus Comestor is probably giving the more accurate account of it by ascribing the pillars to Tubalcain.