George of Hungary

George of Hungary was an Ottoman slave that escaped and reverted from Islam to Christianity, writing afterwards about his experiences. As per his own description, when George was 15 or 16, he was taken prisoner and sold into slavery when the Ottoman Turks invaded the town of Szászsebes in 1438. George had arrived to the city a year earlier, probably to go to a school in the local Dominican monastery.
He would spend 20 years being a slave before he could escape, later becoming a monk in Rome. Here, he wrote Tractatus de moribus, condicionibus et nequitia Turcorum, published in 1481 in Latin. In 1539 it was translated in German language along with a preface by Martin Luther.
The ethnicity of George is not known, possibly being either a German or a Hungarian. It is thought that he grew up in a bilingual environment and did not have a clear concept of his national identity. After his escape from the Ottomans, George condemned Islam.