  We develop a model-independent analysis of hadronic scattering data in the
resonance region, where the resonance shape follows from the matrix elements of
a Hamiltonian. We investigate the rho meson in the tau decay. We demonstrate
that the rho meson resonance in the two-pion decay of the tau lepton is
described well through the coupling of a bare rho meson to the two-pion and the
four-pion continuum. Furthermore, this four-pion continuum corresponds with the
data of the four-pion decay channel of the tau lepton at energies up to 1.1
GeV.
