Complex sentence: Records show that it was in cultivation in Byzantine Egypt; however, there is not yet evidence that it was grown elsewhere, as it is not mentioned in late classical works on farming, natural history, geography or medicine.
Split into simpler sentences: Records show that it was in cultivation in Byzantine Egypt. Elsewhere, however, there is not yet evidence that it was grown, as it is unmentioned in late classical works on farming, natural history, geography or medicine.