Consequently, although the presence of either quicklime or saltpeter in the mixture cannot be entirely excluded, they were not the primary ingredient. Most modern scholars agree that Greek fire was based on either crude or refined petroleum, comparable to modern napalm. The Byzantines had easy access to crude oil from the naturally occurring wells around the Black Sea (e.g., the wells around Tmutorakan noted by Constantine Porphyrogennetos) or in various locations throughout the Middle East. An alternate name for Greek fire was "Median fire" (), and the 6th-century historian Procopius records that crude oil, called "naphtha" (in Greek: "naphtha", from Old Persian "naft") by the Persians, was known to the Greeks as "Median oil" (). This seems to corroborate the availability of naphtha as a basic ingredient of Greek fire.