  Using first-principles only, we calculate the melting point of MgO, also
called periclase or magnesia. The random phase approximation (RPA) is used to
include the exact exchange as well as local and non-local many-body correlation
terms, in order to provide high accuracy. Using the free energy method, we
obtain the melting temperature directly from the internal energies calculated
with DFT. The free energy differences between the ensembles generated by the
molecular dynamics simulations are calulated with thermodynamic integration or
thermodynamic perturbation theory. The predicted melting temperature is
$T_m^\text{RPA} =3043\pm 86$ K, and the values obtained with the PBE and SCAN
functionals are $T_m^\text{PBE} = 2747 \pm 59$ K and $T_m^\text{SCAN} = 3032\pm
53 $ K.
