Khawarnaq was a medieval castle constructed by the Arab Lakhmids near their capital of al-Hira. The castle is mentioned in both Arabic and Persian sources, albeit it is difficult to determine what information is historical and what is myth.[1]
Würsch, Renate (2013). "Ḵawarnaq". In Yarshater, Ehsan (ed.). Encyclopædia Iranica, Volume XVI/2: Kassites–Kégl, Sándor. London and New York: Routledge & Kegan Paul. pp. 143–145. ISBN 978-1-934283-39-4.