 Búri's background beyond this point is unattested, and he had a son, Borr, by way of an unknown process.Búri is attested in the "Prose Edda", composed in the 13th century by Icelander Snorri Sturluson.The "Prose Edda" includes a quote from a 12th-century poem by skald Þórvaldr Blönduskáld that mentions the figure.