1. Cemâluddin Yakut'ul-Musta’simi (1204-1298):
By cutting the tip of the pencil in a curve, he brought a great improvement in mind-sitte. This innovation made by Yakut is a revolution in the history of calligraphy, he is a Turk. The Ottoman Turks, who came after him, gave the peak works of calligraphy art and gave the right to the Yakut'ul-Mustasım Pen.
2. SHEIKH HAMDULLAH SCHOOL
ŞEYH HAMDULLAH (1429 - 1520) Şeyh Hamdullah from Amasya (1437-1520): His Murakaası (ie his album) is exhibited in the Writing Hall of the Topkapı Palace Museum. He is the teacher of the Sultan II.Bayezid. Sheikh Hamdullah is famous with the title of "qiblet'ul-kuttab" of bihakk. He is a very famous calligrapher who all calligraphers in the Ottoman and other Islamic countries accept as a piri. He gained fame and appreciation especially with his thuluth and naskh writings. It is rumored that the sultan kept the inkwell while writing his writings. He is known as the Master of the Masters. Even his son and groom have trained many calligraphers. He is a calligrapher who formed a school in the Ottoman period.
3. KARAHİSARİ AHMED ŞEMSEDDİN SCHOOL
KARAHİSARİ AHMED ŞEMSEDDİN (? - 1556) He could not get rid of the influence of Iranian calligraphers. Karahisarî, who grew up during the reign of Mimar Sinan and bleached the face of the "şeş pen" writing, was also called Yakut-ı Rum.
4. Hafız Osman Efendi and His School
Hafız Osman Efendi (Hafız Osman bin Ali-1642-1700 m.,? - 1112 h.): Hafız Osman took lessons from Derviş Ali, the superior of the time. Later, on the order of Derviş Ali, he took lessons from Suyolcuzâde Eyyubî Mustafa for a while. After completing his training, he continued with Nefeszâde İsmail Efendi and learned all the subtleties in Sheikh Hamdullah's writings. Thus, he was accepted as the greatest figure after Sheikh Hamdullah in his writings, especially in thuluth and naskh.