Complex sentence: The escape was not successful due to overflowing banks of the Morava River and therefore he was convicted together with a group of about 20 similarly charged students of theology and priests for the crime of attempted unauthorised crossing of the national borders.
Split into simpler sentences: The escape was not successful due to overflowing banks of the Morava River. As a result, he was caught and convicted together with a group of about 20 similarly charged students of theology and priests for the crime of attempted unauthorised crossing of the national borders.