  We obtain sharp parabolic interior and global Schauder estimates for
solutions to nonlocal space-time master equations $(\partial_t +L)^su = f$ in
$\mathbb{R} \times \Omega$, where $L$ is an elliptic operator in divergence
form, subject to homogeneous Dirichlet and Neumann boundary conditions. In
particular, we establish the precise behavior of solutions near the boundary.
Along the way, we prove a characterization of the correct intermediate
parabolic H\"older spaces in the spirit of Sergio Campanato.
