Previous evolution models for one-plate planets have commonly assumed steady-state cooling beneath a rigid lid. Recent 3D numerical models indicate however that conductive lid cooling exhibits early transient stages where the quasi-static assumption is not valid. We apply scaling laws for these transient stages to Mars. A wide range of initial conditions for the Martian mantle reflects the possible consequence of the early differentiation of the planet. Our results display large variations for the timing of early transient cooling from several 100 Ma up to a few Ga indicating that classical quasi-static models cannot describe a significant part of the planet's evolution. This suggests new scenarios for Mars'-early history with initial heat fluxes in good agreement with values inferred from both gravity and topography data from the MGS mission. ¿ 2001 American Geophysical Union