  Andromeda II (And II) has been known for a few decades but only recently
observations have unveiled new properties of this dwarf spheroidal galaxy. The
presence of two stellar populations, the bimodal star formation history (SFH)
and an unusual rotation velocity of And II put strong constrains on its
formation and evolution. Following Lokas et al. (2014), we propose a detailed
model to explain the main properties of And II involving (1) a gas-rich major
merger between two dwarf galaxies at high redshift in the field and (2) a close
interaction with M31 about 5 Gyr ago. The model is based on
N-body/hydrodynamical simulations including gas dynamics, star formation and
feedback. One simulation is designed to reproduce the gas-rich major merger
explaining the origin of stellar populations and the SFH. Other simulations are
used to study the effects of tidal forces and the ram pressure stripping during
the interaction between And II and M31. The model successfully reproduces the
SFH of And II including the properties of stellar populations, its morphology,
kinematics and the lack of gas. Further improvements to the model are possible
via joint modelling of all processes and better treatment of baryonic physics.
