Cillian is an Irish male given name derived from the Old Irish word cell meaning "church" combined with a diminutive suffix -ín, giving the sense of "little church" or "church-like." This name has been borne by several early Irish saints, most notably the 7th-century missionary Saint Kilian (or Cillian), who evangelized in Franconia (modern-day Germany) and was martyred in Würzburg around 689. Killian or Kilian are the Anglicized forms of Cillian, along with other variants such as Cillín. In modern usage, Cillian has become popular internationally thanks to figures like Irish actor Cillian Murphy. Etymology The name Cillian originates from the Irish word cill ("church") and the affectionate diminutive suffix -ín. Thus, Cillian literally means "little church" and was often used to denote a spiritual or prayerful person. The name can also be linked to saint names in early Irish onomastics, reflecting the spread of Christianity in Ireland. Notable Bearers The most prominent historical bearer is Saint Kilian (Irish: Cillian), an Irish missionary born around 640 in Mullagh, County Cavan, Ireland. According to the Acta Sanctorum, he journeyed to the continent with twelve companions from Kilmacologue in County Kerry. In Franconia, he preached Christianity and was martyred in Würzburg in 689, later becoming the city's patron saint. Other early Irish saints named Cillian include missionaries to Artois, France, and the author of the life of Saint Brigid. In contemporary culture, Cillian Murphy (born 1976) is a renowned Irish actor known for his roles in films such as 28 Days Later, Inception, and the television series Peaky Blinders. Cultural Significance In Ireland, Cillian remains a traditional name, while the Anglicized versions Kilian and Killian are common among Irish diaspora communities. In continental Europe, particularly in Germany and France, the name is prevalent in forms such as Kilian, Killian, or Kylian. Saint Kilian is venerated in Bavaria, and his feast day is celebrated on July 8. Key Facts Meaning: Pet or diminutive term for church ("little church") Origin: Old Irish cell (church) + -ín (diminutive suffix) Type: First name Main Usage Regions: Ireland, with variants in English-, German-, French- and Spanish-speaking countries