Fire altar (left) (from W. Hinz,
Darius und die Perser, 1976
"He teaches the science of the Magians, owing to Zarathustra, son of Ahuramazda. It is in fact the worship of the gods."
This short quote is interesting for another reason: it connects the activities of the Magians explicitly to Zoroastrianism (which is not necessarily the same as the cult of Ahuramazda). Since we are certain that Magians were involved in the state religion, the words of pseudo-Plato suggest that Zoroastrianism was the official cult of ancient Persia. This is, however, far from certain, and we should not rely too much on an author who believes that the prophet Zarathustra was the son of the god Ahuramazda.
The lan-sacrifice probably was a kind of fire sacrifice, because the Persepolis fortification tablets also call the Magians 'fire kindlers'. The Greek geographer Strabo of Amasia (64 BCE-c.23 CE) translates this as pyrethoi and is a more explicit about this ritual.
"In Cappadocia -for there the sect of the Magians, who are also called fire kindlers, is large- they have fire temples [pyrethaia], noteworthy enclosures; and in the midst of these is an altar, on which there is a large quantity of ashes and where the Magians keep the fire ever burning. And there, entering daily, they make incantations for about an hour, holding before the fire their bundle of rods and wearing round their heads high turbans of felt, which reach down their cheeks far enough to cover their lips."
[Strabo, Geography 15.3.15]
The lips were probably covered to prevent their breath to pollute the fire. How one can sing in this way, is one of the unsolved mysteries of ancient religion. From the holy book of Zoroastrianism, the Avesta, we know that the felt turban is called pâdam and the sacred twigs barsom.
Another interesting observation is that the Magians are never mentioned in connection to non-Iranian gods in the Fortification tablets. Their only activities seem to have been the lan-sacrifice to Ahuramazda on behalf of the king and sacrifices to other Persian gods. Probably, the other sacrifices were similar to those described by Herodotus.