The Real Dirac Equation
Dirac's leaping insight that the normalized anti-commutator of the γ^μ matrices must equal the timespace signature η^μν was decisive for the success of his equation. The γ^μ-s are the same in all Lorentz frames and "describe some new degrees of freedom, belonging to some internal motion in the electron". Therefore, the imposed link to η^μν constitutes a separate postulate of Dirac's theory. I derive a manifestly covariant first order equation from the direct quantization of the classical 4-momentum vector using the formalism of Geometric Algebra. All properties of the Dirac electron & positron follow from the equation - preconceived 'internal degrees of freedom', ad hoc imposed signature and matrices unneeded. In the novel scheme, the Dirac operator is frame-free and manifestly Lorentz invariant. Relative to a Lorentz frame, the classical spacetime frame vectors e^μ appear instead of the γ^μ matrices. Axial frame vectors (without cross product) of the 3D orientation space defining spin and rotations appear instead of the Pauli matrices; polar frame vectors of the 3D position space naturally define boosts, etc. Not the least, the formalism shows a significantly higher computational efficiency compared to matrices.