Introduction
Kay Kavus is the second king of the Kayanian dynasty, son of Kay Kobad and father of the tragic prince Siyavash. He is portrayed in the Shahnameh as a capable but deeply flawed ruler, repeatedly led astray by pride and impulsiveness into disastrous schemes, from which he is usually rescued by the hero Rostam.
This article follows the Zoroastrian and Shahnameh traditions, noting where the older Avestan material and Ferdowsi's later epic differ.
Family
The Mazandaran campaign
Early in his reign, Kay Kavus launched an ill-advised campaign against the demons of Mazandaran, ignoring warnings against the venture. His army was defeated and Kay Kavus himself captured and blinded by the White Div, requiring Rostam to undertake his famous Seven Labours (Haft Khan) to rescue the king and his forces, and to slay the White Div, whose gall was used to restore Kay Kavus's sight.
The flight to heaven
In another episode illustrating his characteristic pride, Kay Kavus, persuaded by a demon in disguise, attempted to build a flying throne by attaching eagles to it, hoping to ascend to heaven like the sun; the eagles, exhausted, eventually crashed him back to earth, a humiliating failure that Ferdowsi presents as a warning against overreaching ambition.
Family tragedy
Kay Kavus's marriage to Sudabeh, and her later false accusation against his son Siyavash after the prince rejected her advances, sets in motion one of the Shahnameh's great tragedies: Siyavash's trial by fire, his exile to Turan, and his eventual execution there, events that Kay Kavus, despite his own role in the family's unraveling, mourns deeply.