Suhrawardi found, and lost, his most important patron in the same young man. Arriving in Aleppo around 1183, the year the Ayyubid sultan Saladin conquered the city and installed his son al-Malik al-Zahir as governor, Suhrawardi became the prince's court philosopher and, by most contemporary accounts, a genuinely close and trusted advisor. It was under that protection that he wrote his major synthesis, Hikmat al-Ishraq, the Philosophy of Illumination, combining Aristotelian logic and metaphysics as transmitted through the Islamic Peripatetic tradition with older Persian and Platonic themes of light, arranging reality as a hierarchy of immaterial lights of varying intensity descending from a single Light of Lights, and arguing that mystical intuition, disciplined and rigorous rather than merely emotional, stands alongside demonstrative reasoning as a genuine source of philosophical knowledge.
That synthesis, and the political shape it implied, a mystical philosopher-king uniting temporal and spiritual authority, alarmed Aleppo's religious establishment, whose scholars drafted a formal legal opinion charging him with doctrines they read as antinomian and with claiming a spiritual rank that rivaled prophecy itself, charges that also worried Saladin, who read them against the memory of the Ismaili movement he had recently suppressed in Egypt and Syria and was unwilling, while still consolidating Ayyubid religious authority after retaking Jerusalem in 1187, to be seen tolerating. Saladin wrote to his son ordering the execution, and the same prince who had sheltered Suhrawardi as a favored court philosopher was left to carry it out at Aleppo in 1191, when Suhrawardi was still in his thirties.