- Verification predates writing; around 3300 BC, sealed clay envelopes with redundant marks evolved into writing itself.
- Ancient civilizations had checksums, audits, inverse-operation verification, acceptance tests, split-key authentication, and signed certificates.
- Athens' 375/4 BC coin law carved a complete verification system into marble: written spec, daily verifier, per-defect actions, and sanctions on the checker.
- Ancient checks had known limits: casting-out-nines misses errors divisible by nine; the Talmud admitted its letter-count expertise had decayed.
- The 20th century added formal specifications as theorems (for all inputs) and automated verifiers that can themselves be verified.