Cían is a Gaelic given name meaning "ancient". Cian was the eighth most popular Irish boys name in Ireland in 2003.
In Irish mythology, Cían (, "long, enduring, far, distant"), also known as Scal Balb, son of Dian Cecht of the Tuatha Dé Danann, is best known as the father of Lug. In most versions, Lug's mother is the Fomorian princess Ethniu, but in some versions Cian is also known as Ethlend, hence Lug is known as Lug mac Ethlend
In the saga Cath Maige Tuired Cian's union with Ethniu is a dynastic marriage following an alliance between the Tuatha Dé and the Fomorians. In the Lebor Gabála Érenn Cian gives the boy to Tailtiu, queen of the Fir Bolg, in fosterage.
Cían's demise, and the consequent revenge by his son Lugh, forcing on the perpetrators the impossible quest for treasures is given in Oidheadh Chloinne Tuireann ("The Fate of the Children of Tuireann"), the full romance of which only survives in late manuscripts, though synopses of the tale survive in medieval redactions of the Lebor Gabála Érenn (LGE). The story goes that Cían was killed by the sons of Tuireann—Brian, Iuchar and Iucharba—after trying unsuccessfully to escape from them in the form of a pig (or a "lapdog", in LGE). Lug set them a series of seemingly impossible quests as recompense. They achieved them all, but were fatally wounded in completing the last one. Despite Tuireann's pleas, Lug denied them the use of one of the items they had retrieved, a magic pigskin which healed all wounds. They died of their wounds, and Tuireann died of grief over their bodies.