  A general class of deformations of integrable sigma-models with symmetric
space F/G target-spaces are found. These deformations involve defining the
non-abelian T dual of the sigma-model and then replacing the coupling of the
Lagrange multiplier imposing flatness with a gauged F/F WZW model. The original
sigma-model is obtained in the limit of large level. The resulting deformed
theories are shown to preserve both integrability and the equations-of-motion,
but involve a deformation of the symplectic structure. It is shown that this
deformed symplectic structure involves a linear combination of the original
Poisson bracket and a generalization of the Faddeev-Reshetikhin Poisson bracket
which we show can be re-expressed as two decoupled F current algebras. It is
then shown that the deformation can be incorporated into the classical model of
strings on R x F/G via a generalization of the Pohlmeyer reduction. In this
case, in the limit of large sigma-model coupling it is shown that the theory
becomes the relativistic symmetric space sine-Gordon theory. These results
point to the existence of a deformation of this kind for the full Green-Schwarz
superstring on AdS5 x S5.
