  We have recently completed the one loop calculation of meson-meson scattering
within Chiral Perturbation Theory. Once unitarized, these amplitudes provide
simultaneously a remarkable description of the resonance region up to 1.2 GeV
as well as the low energy region, respecting the chiral symmetry expansion. The
position of the poles in these amplitudes is related to the mass and width of
the associated resonances that are generated without being explicitly included
in the Lagrangian. The spectroscopic nature of these states can then be deduced
by studying the behavior of these poles, through the Nc dependence of the
Chiral Perturbation Theory parameters, which can be obtained from QCD in the
large Nc limit.
