  We present the result of radio and optical observations of the S0 galaxy IC
4200. We find that the galaxy hosts 8.5 billion solar masses of HI rotating on
a ~90 deg warped disk extended out to 60 kpc from the centre of the galaxy.
Optical spectroscopy reveals a simple-stellar-population-equivalent age of 1.5
Gyr in the centre of the galaxy and V- and R-band images show stellar shells.
Ionised gas is observed within the stellar body and is kinematically decoupled
from the stars and characterised by LINER-like line ratios.We interpret these
observational results as evidence for a major merger origin of IC 4200, and
date the merger back to 1-3 Gyr ago.
