Magnetohydrodynamics is a field in physics which is concerned with large-scale magnetic behaviour of plasmas and liquid metals. Classical results on the analysis and numerical approximations for the deterministic magnetohydrodynamic (MHD) equations (for a viscous incompressible resistive fluid) will be reviewed in a series of talks, with a long-term aim of extending these results to the stochastic setting. In this presentation, I will discuss some physical backgrounds and classical results on well-posedness of the MHD equations due to Duvaut & Lions (1972) and Sermange & Temam (1982).