Cystennin as a Baby Name. Meaning and Origin of Cystennin

What is the meaning of the name Cystennin ?

The baby name Cystennin is a Male name , 3 syllables long and is pronounced /kəsˈtɛnɪn/ (approx. "kuh-STEN-in").

Cystennin is Welsh in Origin.

Cystennin is the Welsh form of Constantine, ultimately from Latin Constantinus, derived from constans “steadfast, faithful.” The name entered Brittonic early, yielding Welsh spellings Cystennin and Middle Welsh Custennin, with the typical Latin -inus > Welsh -in ending. Cognates include Cornish Kostentyn, Breton Konstantin, Irish Constantín, Scottish Gaelic Causantín, and English Constantine.

Medieval Welsh literature and hagiography preserve the name: Custenhin/Custennin appears in the Mabinogion, while Cystennin Fendigaid denotes Constantine the Great in genealogies. A church and parish in Conwy, Llangystennin (“St Cystennin’s church”), commemorate a saint of this name, though traditions differ on whether he was the emperor or a local early medieval holy man. The name is rare in contemporary Wales but persists in scholarly, literary, and heritage contexts, and occasionally sees revivalist use. Variant spellings: Cystennin, Custennin; related English surnames include Costin and Constantine. Meaning centers on steadfastness, reliability, and constancy.

⚙ Cystennin is absent from every birth registry and name dataset we follow. That's typically a sign of a rare name, a regional or traditional one, or a modern coinage. Either way, it remains a genuinely rare choice.