János was born in June 1826 in Eger and his baptism took place there on June 24th, 1826.1 János' father was Ferenc Körtvélyesy and his mother was Mária Gyenes. His paternal grandparents were József Körtvélyesi and Anna Takács. He had three brothers and a sister, named Ignác, Ignác, Ferenc and Mária. He was the third oldest of the five children. He had a half-brother named Ferenc.