  We present two simple dynamical models for Sagittarius based on N-body
simulations of the progressive disruption of a satellite galaxy orbiting for
12.5 Gyr within a realistic Galactic potential. In both models the satellite
initially has observable properties similar to those of current outlying
dwarfs; in one case it is purely stellar while in the other it is embedded in
an extended massive halo. The purely stellar progenitor is a King model with a
total velocity dispersion of 18.9 km/s, a core radius of 0.44 kpc and a tidal
radius of 3 kpc. The initial stellar distribution in the other case follows a
King profile with the same core radius, a slightly larger total velocity
dispersion and similar extent. Both these models are consistent with all
published data on the current Sagittarius system, they match not only the
observed properties of the main body of Sagittarius, but also those reported
for unbound debris at larger distances.
