a distance modulus of $(m-M)_{V} = 11.57 \pm 0.13$ and a metallicity of $[M/H] = +0.045 \pm 0.044$ which are in good agreement with previous measurements. The age of M37 is thus comparable to that of the Hyades [625 Myr with overshooting; @Perryman.98] which at present is the oldest cluster for which a significant number of stellar rotation periods have been measured. M37 is, however, substantially richer than the Hyades and thus has the potential to provide a much larger data-set of rotation periods for older stars.

As we were preparing to submit this manuscript, we became aware of a similar, independent study by @Messina.08, which presents rotation periods for 122 stars in this cluster. Our survey goes more than 2 magnitudes deeper than @Messina.08 with more than an order of magnitude more observations from more than twice as many nights. As a result we are able to study the rotation evolution for late K and early M dwarfs as well as the late F, G and early K dwarfs studied by @Messina.08. On the other hand, the @Messina.08 survey has measured periods for early F stars that are saturated in our survey. We compare the periods measured by both 