Sepandiār or Esfandiyār (Persian: سپنديار), also transliterated as Sepandiyar, Esfandyar, Isfandiar, Isfandiyar or Esfandiar, was a legendary Iranian hero also known as Belfian. He was the son and the crown prince of the Kayanian King Goshtasp (from Middle Persian Wishtasp from Avestan language Vishtaspa) and brother of the saintly Pashotan (Middle Persian Peshotan, Avestan Peshotanu).
The "Sepandiār" of legend is best known from the tragic story of a battle with Rostam, as described in Ferdowsi's epic Shahnameh (Book of Kings). It is one of the longest episodes in Shahnameh, and one of its literary highlights.
The Perso word 'Sepandiār' is derived from Middle Persian 'Spandadat' or 'Spandyat' (the variance is due to ambiguities inherent to Pahlavi script), which in turn derives from Avestan Spentodata "Given by/through bounty" or "Given by (the) holy" (see Amesha Spenta for other meanings of spenta-). The Median language *Spendata – as it is reconstructed – probably motivated a similar Old Persian form, which may be inferred from Greek Sphendadates, a 5th-century BCE political figure unrelated to the Esfandiar of legend. Equally unrelated is the Sassanid-era feudal house of Spandyat, that – like numerous other feudal houses also – adopted a Kayanian name in order to legitimize and emphasize the antiquity of their genealogy.
In the Shahnameh
According to the epic – the Shahnameh – Sepandiār (Esfandiyār) was the Crown Prince and a Divine Warrior of ancient Iran (or Persia) who supported the prophet Zartosht (Zarathustra), enabling him to spread the religion of Zoroastrianism in the land. He also fought against many apostates and enemies of Zartosht to do so. In return, Zartosht gave Esfandiyār an armor and a chain from Heaven. the armor made him invincible and the chain had the power to bind any demon or evil magician making them unable to escape. Zartosht also blessed the prince and declared that anyone who would spill the blood of Esfandiyār (kill him) would suffer a cursed life of bad omens until the day he dies, and even after death would be condemned to hell, thus turning him into the sacred prince with Divine splendor of Ahura Mazda.
In the famous story of Rostam's fight against Esfandiyār, the Simurgh warned Rostam that prince Esfandiyār is a blessed divine prince and his killer would be cursed. He told Rostam that there would be no shame in surrendering to his Divine splendor. But Rostam refuses to accept the shame of being in chained and so Simurgh then helped Rostam defeat the prince, as follows:
Esfandiyār's father, Goshtasp, had promised to give him the throne if he manages to repel an invasion in far-off provinces. Esfandiyār successfully carries out, but upon his return his father informs him that during his absence king of Turan Arjaasb had rebelled and attacked Iran's capital and abducted Esfandiyār's two sisters and sends Esfandiyār on another mission to suppress the rebellion in and retrieve the abducted princesses. Esfandiyār sets out in hurry passing through a difficult and dangerous way with 7 different battles which would be known later as 7 labors of Esfandiyār. Esfandiyār then successfully infiltrates the Fortress of Arjaasb known as Roin Dej literally meaning Invincible Fortress killing Arjaasb, rescuing his sisters and conquering the fortress. Upon his return to Iran Goshtasp who did not like to part with his throne hedges once again and – although he is aware of a prediction that foretells the death of Esfandiyār at the hand of Rostam – compels the young hero to go and bring the aging Rostam in chains for his arrogance and disrespect toward the king, promising that upon completing this mission he will certainly this time gives the throne to Esfandiyār and retire himself. Although Esfandiyār initially protests, reminding his father of Rostam's fame, great age and services to the dynasty, he eventually complies with his father's wishes and sets out towards Rostam.
Upon reaching the home of Rostam, Esfandiyār delivers the message, but Rostam refuses to comply with being put in chains, accepting only to accompany the young prince to his father's palace. Esfandiyār insists, but Rostam – although making numerous concessions – stands his ground, and the two eventually meet in single combat. In the subsequent battle, the invincible Esfandiyār is unaffected by Rostam's blows while Rostam is seriously wounded by Esfandiyār's arrows which had diamond arrowheads and could easily pierce through Rostam's Armor.
Pleading respite to dress his wounds, Rostam withdraws, where he learns from the Simurgh of the only weapon that can affect Esfandiyār: a shot to the eyes from a special double-headed arrow made from the branch of a tamarisk tree near the see of china. The Simurgh warns Rostam about the fate that awaits the killer of Esfandiyār and asks Rostam to consider surrendering to the Prince. But Rostam refuses to accept the shame of surrendering and being in chained by anyone and upon making this decision Simurgh carries Rostam to the Tamarisk tree where Rostam fashions the double head arrow with a feather of Simurgh and a twig of a tamarisk tree, and when the battle resumes the next morning, Esfandiyār is blinded by a shot through the eyes.
In the end before dying, Esfandiyār confesses that it was the false promise of his father Goshtasp who did not want to part with his throne, and the Arrow of Simurgh that killed him; and Rostam is not guilty in this, but his real murderer who should be cursed and blamed is Goshtasp.