A Persian king reportedly sent an army to punish this oracle and lost the entire force before it arrived, a story ancient enough that it may already have been part legend when it was first written down.
Cambyses' lost army
The Greek historian Herodotus reports that the Persian king Cambyses II sent an army of many thousands to destroy the Oracle of Amun after a dispute, and that the entire force vanished, allegedly buried by a desert sandstorm, somewhere in the open desert before reaching Siwa. No confirmed archaeological trace of the army has been found despite periodic searches and occasional unverified claims of discovery, and many historians treat the story as at least partly legendary embellishment rather than a fully reliable historical record.
A temple built into a cliff
The oracle itself operated from the Temple of the Oracle at Aghurmi, built into a rock outcrop, where priests are understood to have delivered pronouncements attributed to Amun through methods not fully described in surviving sources, a gap in the record that leaves the oracle's actual working mechanism, unlike Delphi's more documented rituals, largely unknown.
An oasis with its own culture
Siwa's population is predominantly Siwi, a Berber, or Amazigh, people with their own distinct language and customs, historically set apart from mainstream Egyptian Arabic-speaking culture by the oasis's extreme geographic isolation, a separateness that shaped the oracle's own reputation as a place answering to different authority than the rest of Egypt.