piety

n. devoutness, orthodoxy; religiousness, piousness

In spiritual terminology, piety is a virtue. While different people may understand its meaning differently, it is generally used to refer either to religious devotion or to spirituality, or often, a combination of both. A common element in most conceptions of piety is humility.
See more at Wikipedia.org...

Noun
1. righteousness by virtue of being pious
(synonym) piousness
(antonym) impiety, impiousness
(hypernym) righteousness
(hyponym) devoutness, religiousness
(attribute) pious

(n.)
Veneration or reverence of the Supreme Being, and love of his character; loving obedience to the will of God, and earnest devotion to his service.
  

(n.)
Duty; dutifulness; filial reverence and devotion; affectionate reverence and service shown toward parents, relatives, benefactors, country, etc.
  

Just as faith was an important medieval virtue of particular importance to knights , piety kept that faith strongly held.