We have obtained V and I images of the lone globular cluster that belongs to the dwarf Local Group irregular galaxy known as WLM .
The color-magnitude diagram of the cluster shows that it is a normal old globular cluster with a well-defined giant branch reaching to M _ { V } = -2.5 , a horizontal branch at M _ { V } = +0.5 , and a sub-giant branch extending to our photometry limit of M _ { V } = +2.0 .
A best fit to theoretical isochrones indicates that this cluster has a metallicity of [ Fe/H ] = -1.52 \pm 0.08 and an age of 14.8 \pm 0.6 Gyr , thus indicating that it is similar to normal old halo globulars in our Galaxy .
From the fit we also find that the distance modulus of the cluster is 24.73 \pm 0.07 and the extinction is A _ { V } = 0.07 \pm 0.06 , both values that agree within the errors with data obtained for the galaxy itself by others .
We conclude that this normal massive cluster was able to form during the formation of WLM , despite the parent galaxy ’ s very small intrinsic mass and size .