Sisillius III explained

Sisillius III was a legendary king of the Britons as accounted by Geoffrey of Monmouth. He reigned approximately 173–167BC.^[1]

He was preceded by Oenus^[2] and succeeded by Beldgabred. He shares his name with one of the sons of Ebraucus and his ancestors Sisillius II and Sisillius I.

Notes and References

1. http://www.monarchie-noblesse.net/angleterre/bretons/bretons.htm Monarchie Nobelesse website, Bretons
2. https://www.library.wales/fileadmin/docs_gwefan/new_structure/discover/digital_exhibitions/printed_material/welsh_classical_dictionary/09_OPR.pdf National Library of Wales, Welsh Classical Dictionary page 584