The Star Formation Histories of the M31 and M33 Spheroids
  I review the observational constraints on the star formation histories in the
spheroids of M33 and M31, the other two spiral galaxies in the Local Group. M33
does not possess a traditional bulge; instead, it has a small nuclear region
hosting stars with a wide range of ages. The star formation history of the M33
halo is poorly constrained, but composite spectra of its halo globular clusters
imply a wide age spread of 5 - 7 years, while the presence of RR Lyrae stars in
the halo implies at least some of the population is ancient. Although it is
possible to obtain the detailed star formation history of the M33 halo via deep
photometry, this has not been done to date. M31 hosts a traditional bulge that
is apparently dominated by stars older than 10 Gyr. Deep photometry of the M31
halo demonstrates that it hosts both a population of ancient metal-poor stars
and a significant population extending to younger ages and high metallicity,
apparently due to its active merger history.
