Calculus of variations & optimal control
Extremizing functionals — and, later, optimally steering dynamical systems over time.
Founded: 1696 — Johann Bernoulli's brachistochrone challenge
The claim
No credible dismissal found. True in none of the three eras checked: classical Bernoulli/Euler/Lagrange, the 20th-century functional-analytic “direct method” reformulation, and Pontryagin/Bellman-era optimal control.
What happened
Rocket trajectory optimization (1956) — Pontryagin's maximum principle, created explicitly for this purpose.
0 years — applied from inception in every era — no meaningful gap
Verdict: Never dismissed, applied anyway.
Confidence: medium-high.