  We perform an analysis of the QCD lattice data on the baryon octet and
decuplet masses based on the relativistic chiral Lagrangian. The baryon self
energies are computed in a finite volume at next-to-next-to-next-to leading
order (N$^3$LO), where the dependence on the physical meson and baryon masses
is kept. The number of free parameters is reduced significantly down to 12 by
relying on large-$N_c$ sum rules. Altogether we describe accurately more than
220 data points from six different lattice groups, BMW, PACS-CS, HSC, LHPC,
QCDSF-UKQCD and NPLQCD. Values for all counter terms relevant at N$^3$LO are
predicted. In particular we extract a pion-nucleon sigma term of 39$_{-1}^{+2}$
MeV and a strangeness sigma term of the nucleon of $\sigma_{sN} = 84^{+
28}_{-\;4}$ MeV. The flavour SU(3) chiral limit of the baryon octet and
decuplet masses is determined with $(802 \pm 4)$ MeV and $(1103 \pm 6)$ MeV.
Detailed predictions for the baryon masses as currently evaluated by the ETM
lattice QCD group are made.
