During the 19th century hundreds of schools were constructed by Pontic Greek communities in the Trebizond Vilayet, giving the region one of the highest literacy rates in the Ottoman Empire. The Greeks of Caykara, who according to Ottoman tax records converted to Islam during the 17th century, were also recognized for their educational facilities. Teachers from the Of-valley provided education for thousands of Anatolian Sunni and Sufi students in home schools and small madrassas. Some of these schools taught Pontic Greek alongside Arabic (and to a lesser extent Persian or Ottoman Turkish as well). Although Atatürk banned these madrassas during the early republican period, some of them remained functioning until the second half of the 20th century because of their remote location. The effects of this educational heritage continue to this day, with many prominent religious figures, scientists and politicians coming from the areas influenced by the Naqshbandi Sufi orders of Pontic Greek extraction in Of, Caykara and Rize, among them president Erdogan, whose family originates from the village of Potamia.