But if he refuses, then I will come quickly."[23] Despite the extensive fortifications of the city and its 400 cannon manned by 2,000 artillerymen, Ismail Bey caved in to Mehmed's demands, and accepted the lands Mehmed gave him in Thrace. There he wrote a work on ritual prescriptions of Islam called Huulviyat-i Sultan, and died in 1479.[24]