  The light curve of SN 1572 is described in the terms used nowadays to
characterize SNeIa. By assembling the records of the observations done in
1572--74 and evaluating their uncertainties, it is possible to recover the
light curve and the color evolution of this supernova. It is found that, within
the SNe Ia family, the event should have been a SNIa with a normal rate of
decline, its stretch factor being {\it s} $\sim$ 0.9. Visual light curve near
maximum, late--time decline and the color evolution sustain this conclusion.
After correcting for extinction, the luminosity of this supernova is found to
be M$_{V}$ $=$ --19.58 --5 log (D/3.5 kpc) $\pm$ 0.42.
