  We present an overview of the correlation-matrix methods developed recently
by the CSSM Lattice Collaboration for the isolation of excited states of the
nucleon. Of particular interest is the first positive-parity excited-state of
the nucleon known as the Roper resonance. Using eigenvectors of the correlation
matrix we construct parity and eigenstate projected correlation functions which
are analysed using standardized methods. The robust nature of this approach for
extracting the eigenstate energies is presented. We report the importance of
using a variety of source and sink smearings in achieving this. Ultimately the
independence of the eigenstate energies from the interpolator basis is
demonstrated. In particular we consider $4\times 4$ correlation matrices built
from a variety of interpolators and smearing levels. Using FLIC fermions to
access the light quark mass regime, we explore the curvature encountered in the
energy of the states as the chiral limit is approached. We report a low-lying
Roper state contrasting earlier results using correlation matrices. To the best
of our knowledge, this is the first time a low-lying Roper resonance has been
found using correlation matrix methods. Finally, we present our results in the
context of the Roper results reported by other groups.
