Presumably he was identical with a certain ispán Achilles, who was mentioned in a royal charter issued in 1184, where an investigation took place on the subject of serfs' affiliation in Úrkút.[1]
(in Hungarian) Markó, László (2006). A magyar állam főméltóságai Szent Istvántól napjainkig – Életrajzi Lexikon ("The High Officers of the Hungarian State from Saint Stephen to the Present Days – A Biographical Encyclopedia") (2nd edition); Helikon Kiadó Kft., Budapest; ISBN963-547-085-1
(in Hungarian) Zsoldos, Attila (2011). Magyarország világi archontológiája, 1000–1301 ("Secular Archontology of Hungary, 1000–1301"). História, MTA Történettudományi Intézete. Budapest. ISBN978-963-9627-38-3