Lower, Mark A (1860) Patronymica Britannica: a dictionary of the family names of the United Kingdom. London: J.R. Smith. Public Domain.
CECIL
As described in historical dictionaries
Patronymica Britannica (1860)
CECIL. The name of this noble family was written in ancient times, Sitailt, Sicelt, Seycil, Seisil, Cyssell, kc, until William Cecil, Lord Burghley, Queen Elizabeth's famous minister, from a whimsical notion that he was descended fi'om the Roman Cascilii, adopted the present orthography. The iiimily, doubtless of Norman origin, can be traced to Roliert Sitsilt, M'ho in 1091 assisted Robt. Fitz-Hamon in the conquest of Glamorganshire. Collins.
Surname type: From given name or forename
Origin: English
Region of origin: British Isles
Country of origin: England
Religion of origin: Christian
Language of origin: English