prevalence (n.)

1590s, "fact of having mastery," from French prévalence (15c.), from Medieval Latin praevalentia "superior force," from Latin praevalens, present participle of praevalere "to be more able," from prae "before" (see pre-) + valere "have power, be strong" (from PIE root *wal- "to be strong"). Meaning "condition of being widespread or general" is from 1713. Shakespeare has prevailment.