According to the prologue of Neilos' work on the patriarchs, he was in Palermo in 1142/43 at the court of king Roger II of Sicily. His signature appears at the bottom of an act, dated 1146, regarding the church of the Martorana in Palermo.[2] Everything else regarding his life is a matter of conjecture. Born into a Greek-Sicilian family with the name "Nicholas" he apparently made his career in Constantinople, where he held various high offices, both ecclesiastical and secular: deacon of the Hagia Sophia, patriarchal notary, protoproedros of the protosynkelloi and nomophylax.[2][3] At some point he became a monk, assuming the monastic name "Neilos", and left for Sicily.[1]