Ciaran is an Irish male given name derived from the Old Irish word ciar, meaning "black" or "dark". The name can be traced back to the 5th century AD and is associated with the early Christian saints of Ireland.

It is believed that the name Ciaran was first popularized by Saint Ciaran of Saigir, who lived from around 512 to 588 AD. He was an Irish monk and missionary who founded the monastery of Seir-Kieran in County Offaly, Ireland. Saint Ciaran is venerated in the Catholic Church and his feast day is celebrated on March 5th.

Another prominent figure in the history of the name Ciaran was Saint Ciaran of Clonmacnoise, who lived from around 516 to 549 AD. He was an Irish abbot and founder of the famous monastery of Clonmacnoise in County Offaly. Saint Ciaran of Clonmacnoise is also venerated in the Catholic Church, and his feast day is celebrated on September 9th.

In the Middle Ages, the name Ciaran was popular among Irish nobility and rulers. One notable example is Ciaran mac Máel Chróin, who was the King of Munster from 975 to 976 AD. Another historical figure with this name was Ciaran of Bellachmugha, a 12th-century Irish poet and religious scholar.

During the modern era, the name Ciaran has been carried by several notable individuals, such as Ciaran Hinds (born 1953), an Irish actor known for his roles in films like "Munich" and "Harry Potter and the Deathly Hallows: Part 2". Ciaran Carson (1948-2019) was an acclaimed Irish poet and writer, while Ciaran Byrne (born 1983) is an Irish professional boxer.

Other notable individuals with the name Ciaran include Ciaran Cuddihy (born 1963), an Irish former hurler who played for Waterford, and Ciaran O'Keeffe (born 1985), an Irish former professional footballer who played for clubs like Everton and Sunderland.