  We evaluate in great detail one-loop four-graviton field theory amplitudes in
pure N=4 D=4 supergravity. The expressions are obtained by taking the field
theory limits of (4,0) and (2,2) space-time supersymmetric string theory
models. For each model we extract the contributions of the spin-1 and spin-2
N=4 supermultiplets running in the loop. We show that all of those
constructions lead to the same four-dimensional result for the four-graviton
amplitudes in pure supergravity even though they come from different string
theory models.
