The ancient Zoroastrian method of disposal of the dead is SKY BURIAL. The corpse is placed on a mountaintop to be eaten by carrion birds/vultures, while it is exposed to the rays of the sun and stars.
In Zoroastrianism, death, decay and disease are the handiwork of the diabolic, dark forces. Hence, dead matter called nasuu is considered most unclean and defiled by forces of decay, and destruction.
Accordingly, there is no need to preserve the dead body after death, as it is now a lifeless, contaminated vessel. The birds atop a “special built tower” on a mountaintop or hill, shall strip the flesh, free the spirit, remove the potential for pollution, and reduce the remains to a handful of clean bones.
Special care is made to preclude any possible tainting of the good earth, waters and fire from coming into contact with decaying, dead matter. The word for dead matter nasuu goes back to reconstructed Proto Indo European *neḱ-. Cognates include Latin nex, noxius “harmful, noxious,” and Greek nekrós “dead body.”
The rule is to avoid rotting away, and to dispose the carcass/dead corpse as efficiently and speedily as possible. For that purpose, circular towers called dakhma are constructed on top of desolate mountaintops or high hills. Zoroastrian sky burial practices are first attested in the mid-5th century BCE Histories of Herodotus, but the use of “sky burial towers” is first documented in the early 9th century BCE.
In modern times, circular, raised towers are referred to as “Towers of Silence.” The term is attributed to Robert Murphy, a translator for the British colonial government of India in the early 19th century.
The original word for “sky burial towers” or dakhma denotes the idea of setting “ablaze, aflame.” Avestan dažaiti “burn,” Lithuanian degù “burn,” Old Irish daig “flame” are possibly connected, and cognates.
This suggests that towers of silence were originally raised, built pyres on mountaintops and hills, before the Zoroastrian era. In much of the ancient Iranian lands, the topography is extremely mountainous, and the ground is too hard, rocky, and cold to dig, also, the scarcity of fuel and timber, made sky burial probably much more practical than cremation.
The carved tombs of the Achaemenid Rulers at mountain cliffs in Naqsh-e Rustam, and the raised, above the ground mausoleum in Pasargadae, suggest sky burial practices, until the clean bones could safely be collected and placed in an above the ground astôdán, “ossuary”.
It shall be added, that to avoid any possible contamination of the underground waters and the good earth, any collection of clean mortal remains such as bones, MUST take place in ABOVE THE GROUND vaults, crypt structures, and burial mausoleums, in the ancient, orthodox Zoroastrian practice.
Parallels could be drawn with the funeral of Patroclus as it is described in book 23 of the Iliad. Patroclus is burned on a pyre, and his bones are collected into a golden urn. An above the ground barrow is built on the location of the pyre. Also, Beowulf’s body is taken to Hronesness, where it is burned on a funeral pyre. Afterwards, a mound is built on top of a hill, overlooking the sea, and filled with treasures.
Other important above the ground burial mounds/kurgans are found in Ukraine and South Russia and are associated with much more ancient steppe peoples, notably the Scythians (e.g., Chortomlyk, Pazyryk) and early Indo-Europeans (e.g., Ipatovo kurgan.)
Beside Zoroastrians, the practice of sky burial appears to have been the favored method of the disposal of the dead among the ancient Celts. It is believed that sites close to STONEHENGE were used for sky burial rites.
Sky burial was practiced also among American Indians, and to this day, sky burial is practiced in Tibet, Bhutan and Inner Mongolia, where Vajrayana Buddhist traditions teach that sky burial is the most generous way to dispose of the dead.
REGRETTABLY, in the early twentieth century, the Iranian Zoroastrians gradually discontinued the use of sky burial, and began to favor burial. A former, lush Qajar dynasty era palace, some 10 km from Tehran, by the name of Ghassr-e Firouzeh “Firouzeh’s Palace,” was purchased, and turned into a cemetery. The graves were lined with rocks and plastered with cement to prevent direct contact with the earth.
However, digging graves is in no way in compliance with ancient Zoroastrian disposal practices. In case, that sky burial is under no pristine conditions possible, the only religiously acceptable form of disposal is burial in ABOVE THE GROUND, RAISED vaults, crypt structures, and mausoleums.