  We study what we call the all-loop anisotropic bosonized Thirring sigma
model. This interpolates between the WZW model and the non-Abelian T-dual of
the principal chiral model for a simple group. It has an invariance involving
the inversion of the matrix parametrizing the coupling constants. We compute
the general renormalization group flow equations which assume a remarkably
simple form and derive its properties. For symmetric couplings, they
consistently truncate to previous results in the literature. One of the
examples we provide gives rise to a first order system of differential
equations interpolating between the Lagrange and the Darboux-Halphen integrable
systems.
