  We present a new application of affine Lie algebras to massive quantum field
theory in 2 dimensions, by investigating the $q\to 1$ limit of the q-deformed
affine $\hat{sl(2)}$ symmetry of the sine-Gordon theory, this limit occuring at
the free fermion point. We describe how radial quantization leads to a
quasi-chiral factorization of the space of fields. The conserved charges which
generate the affine Lie algebra split into two independent affine algebras on
this factorized space, each with level 1 in the anti-periodic sector. The space
of fields in the anti-periodic sector can be organized using level-$1$ highest
weight representations, if one supplements the $\slh$ algebra with the usual
local integrals of motion. Using the integrals of motion, a momentum space
bosonization involving vertex operators is formulated. This leads to a new way
of computing form-factors, as vacuum expectation values in momentum space.
