Constantine of Preslav (Bulgarian: Константин Преславски) was a medieval Bulgarian scholar, writer and translator, one of the most important men of letters working at the Preslav Literary School at the end of the 9th and the beginning of the 10th century. Biographical evidence about his life is scarce but he is believed to have been a disciple of Saint Methodius. After the saint's death in 885, Constantine was jailed by the Germanic clergy in Great Moravia and sold as slave in Venice. He escaped to Constantinople, moving to Bulgaria around 886 and working at the Preslav Literary School.