  In recent years the study of two particle systems on the lattice has led to
excellent results in the meson sector of the QCD spectrum, however baryon
resonances mostly remain unexplored. We present a study of pion-nucleon systems
as decay product of baryon resonances in different channels, with special focus
on the nucleon spectrum. We evaluate the correlation functions of single and
multi particle interpolators. All the Wick contributions are explicitly
computed and the consequences of reduced symmetries in moving frames are taken
into account. We discuss the theoretical setup together with results for
$n_f=2$ mass degenerate light quarks.
