Special Relativity From Nonrelativistic Lagrangian Formalism?

  The Lagrangian formalism was originally introduced as a method of deriving Newton’s equations in the nonrelativistic case. Two equations associated with this formalism are: dL/dv = p and H=pv-L where H is the Hamiltonian (often energy) and L the Lagrangian, p momentum and v velocity. If one treats H as E (energy), but  insists that p be energy flow i.e. Ev i.e generalizing mo v, then one may obtain special relativity.