The formation time scales of giant spheroids

We review current progress in the study of the stellar populations of early-type galaxies, both locally and at intermediate redshifts, In particular, we focus on the ages of these galaxies and their evolution in hopes of determining the star formation epochs of their stars. Due to serious remaining systematic uncertainties, we are unable to constrain these epochs precisely. We discuss our results on the evolution of stellar populations in the context of other observables, in particular the evolution of the Fundamental Plane of early-type galaxies.