Context : The formation and evolution of disk galaxies are long standing questions in Astronomy .
Understanding the properties of globular cluster systems can lead to important insights on the evolution of its host galaxy .

Aims : We aim to obtain the stellar population parameters – age and metallicity – of a sample of M31 and Galactic globular clusters .
Studying their globular cluster systems is an important step towards understanding their formation and evolution in a complete way .

Methods : Our analysis employs a modern pixel-to-pixel spectral fitting technique to fit observed integrated spectra to updated stellar population models .
By comparing observations to models we obtain the ages and metallicities of their stellar populations .
We apply this technique to a sample of 38 globular clusters in M31 and to 41 Galactic globular clusters , used as a control sample .

Results : Our sample of M31 globular clusters spans ages from 150 Myr to the age of the Universe .
Metallicities [ Fe/H ] range from –2.2 dex to the solar value .
The age-metallicity relation obtained can be described as having two components : an old population with a flat age- [ Fe/H ] relation , possibly associated with the halo and/or bulge , and a second one with a roughly linear relation between age and metallicity , higher metallicities corresponding to younger ages , possibly associated with the M31 disk .
While we recover the very well known Galactic GC metallicity bimodality , our own analysis of M31 ’ s metallicity distribution function ( MDF ) suggests that both GC systems cover basically the same [ Fe/H ] range yet M31 ’ s MDF is not clearly bimodal .
These results suggest that both galaxies experienced different star formation and accretion histories .

Conclusions :