The history of medieval Zenica is not well recorded. There is but a single item of evidence from 1244 about Croatian-Hungarian king Béla IV's charter. According to the documents that have been studied until so far, the city's current name was first mentioned on 16 March 1436 (or 20 March 1436, annually celebrated as 'Zenica Day') and later – Zenica is mentioned in a series of documents related to Republic of Ragusa (Republic of Dubrovačka). Among other Bosnian parishes, Bored parish, which includes the place "Bilina poila" is mentioned in the charter; the place refers to one part of the town Zenica, today well known Bilino polje. The same place is mentioned in another document, dated 8 April 1203; it records a group of Bogomil chiefs who renounced paternalism before Innocent III's court chaplain John of Casamaris. Bogomilism's presence in the Zenica area and its status as a seat of the Bogomil Church is supported not only by written documents but also by headstones which illuminate the Church's hierarchy.