High-pressure sulphur discharges display two main attractive lighting properties, principally high efficiency and good colouring, which stem from the fact that the light is molecular in origin. However the substantial number of radiative transitions (~105) within the sulphur molecule hampers detailed study. To further our understanding of the discharge we have used the plasma simulation program, PLASIMO , developed at the Equilibrium and Transport in Plasmas (ETP) group in Eindhoven. With PLASIMO we model the LTE energy balance of a high-pressure microwave powered sulphur discharge with some argon as a buffer gas. We present the model and briefly examine the technique used to deal with radiation, the quasi-static or so-called Classical Franck-Condon approach . We find that within the limitations of this approach the spectrum and operational trends reflected in the spectrum can be described.