Nicholas I (Czech: Mikuláš I. Opavský) (c. 1255 – 25 July 1318) was the natural son of Bohemian king Ottokar II Přemysl and his mistress Agnes of Kuenring. In 1269 he became Duke of Opava (at modern day Opava, Czech Republic) and thereby the progenitor of the Silesian cadet branch of the Přemyslid dynasty that lasted until 1521.He was legitimated by his father with the consent of Pope Urban IV and raised at the Prague court.