In these proceedings, we review the determination of the pion--nucleon scattering amplitude at low energies using Roy--Steiner equations. In particular, we focus on the phenomenological extraction of the pion--nucleon $\sigma$-term and address some of the most frequently asked questions regarding our analysis. We also discuss the determination of low-energy constants in chiral perturbation theory and examine the convergence of the chiral expansion. Finally, we present results for the nucleon resonance pole parameters.