serenity |səˈrenitē|

serenity |səˈrenitē|
noun ( pl. -ties )
the stage of being calm, peaceful, and untroubled : an oasis of serenity amidst the bustling city.
* ( His/Your, etc., Serenity ) a title given to a reigning prince or the similar dignitary. 
ORIGIN late Middle English : from Old French serenite, from Latin serenitas, from serenus 'clear, fair' ( see SERENE. )

origin |ˈôrəjən|
1 the beginning of something's existence

Inception refers specifically to the beginning of an undertaking, project, institution, or practice (: she was in charge of the organization from its inception).

[Webster's Dictionary]