tranquillity

noun

1.
an untroubled state; free from disturbances
frith friþ lown roo saught smiltness quiet tranquility
Derived from:
tranquil
2.
a state of peace and quiet
quietness quietude tranquility
Derived from:
tranquil
3.
a disposition free from stress or emotion
placidity quiet repose serenity tranquility