constancy

noun2

1. •
   The quality of being constant; steadiness or faithfulness in action, affections, purpose, etc.

   • A little Water cleares vs of this deed. How easie is it then? your Constancie Hath left you vnattended. — 1606
2. •
   An unchanging quality or characteristic of a person or thing.

   • […] yonger spirits, […] whose constancies Expire before their fashions: […] — 1604