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 ^ { -1 } } , 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 .