Popiel I was a legendary ruler of Poland, member of the Popielids dynasty. According to the legends reported by Wincenty Kadłubek in his Chronica seu originale regum et principum Poloniae, he was the son of Leszko III. Father of Popiel II.
- Jerzy Strzelczyk: Mity, podania i wierzenia dawnych Słowian. Poznań: Rebis, 2007. ISBN 978-83-7301-973-7.
- Jerzy Strzelczyk: Od Prasłowian do Polaków. Kraków: Krajowa Agencja Wydawnicza, 1987. ISBN 83-03-02015-3.