  A detailed study of the Star Formation History of the Sgr dSph galaxy is
performed through the analysis of the data from the Sagittarius Dwarf Galaxy
Survey (SDGS; Bellazzini, Ferraro & Buonanno 1999). Accurate statistical
decontamination of the SDGS Color - Magnitude diagrams allow us to obtain many
useful constraints on the age and metal content of the Sgr stellar populations
in three different region of the galaxy.
  A coarse metallicity distribution of Sgr stars is derived, ranging from
[Fe/H]~ -2.0 to [Fe/H]~ -0.7, the upper limit being somewhat higher in the
central region of the galaxy. A qualitative global fit to all the observed CMD
features is attempted, and a general scheme for the Star Formation History of
the Sgr is derived. According to this scheme, star formation began at very
early time from a low metal content Inter Stellar Medium and lasted for several
Gyr, coupled with progressive chemical enrichment. The Star Formation Rate
(SFR) had a peak from 8 to 10 gyr ago when the mean metallicity was in the
range -1.3<= [Fe/H] <= -0.7. After that maximum, the SFR rapidly decreased and
very low rate star formation took place until ~1-0.5 Gyr ago.
