Who is Shaykh Aq Shams al-Din ibn Hamza, the teacher of Mehmed the Conqueror, and what are the most prominent features of his biography?

Muhammad ibn Hamzah ibn Muhammad ibn Muhammad al-Rumi, Shams al-Din al-Hanafi, known as Ibn al-Fanari, was a scholar proficient in Islamic legal sciences, language, and Qira'at (readings of the Quran). He authored works on Tafsir (Quranic exegesis) and Usul (Islamic legal methodology), and had knowledge of medicine.

He was a Sufi and held Ibn Arabi, the author of Fusus al-Hikam and Al-Futuhat al-Makkiyya, in high esteem. He used to teach and explain Al-Fusus. He was born in the year 751 AH and studied under 'Ala' al-Din, known as al-Aswad, Kamal al-Din Muhammad ibn Muhammad al-Ma'arri, and others. He traveled to Egypt in 771 AH and studied under Sheikh Akmal al-Din.

Upon his return to Anatolia (Rum), he assumed the position of Qadi (judge) in Bursa, then in Konya. He became close to the Ottoman Sultan Mehmed I after the Sultan's victory over the Karamanid Bey, attaining a high status with him, and his virtue became renowned.

Al-Hafiz Ibn Hajar criticized him for embracing Ibn Arabi's doctrine, though he did not display this openly during his visit to Cairo. He performed Hajj in 822 AH and visited Jerusalem. He performed Hajj again in 833 AH after Allah restored his sight following an eye affliction (ophthalmia), and he passed away in Rajab of the same year.

Sultan Mehmed the Conqueror held him in great reverence. It is narrated that the Sultan visited him, but the Sheikh did not rise for him. When the Sultan asked to enter his private retreat (khalwa), the Sheikh refused, saying that if the Sultan were to enter it, he would experience a pleasure that would cause the sultanate to diminish in his eyes, and that the purpose of the retreat was to achieve justice. So the Sultan stood up and bid him farewell while the Sheikh remained reclined. Ibn Wali al-Din clarified that the Sheikh intended to ward off arrogance from the Sultan due to the great victory he had achieved.