We report on the discovery of the z = 1.016 cluster RzCS 052 using a modified red sequence method , followup spectroscopy and X-ray imaging . This cluster has a velocity dispersion of 710 \pm 150 km s ^ { -1 } , a virial mass of 4.0 \times 10 ^ { 14 } M _ { \odot } ( based on 21 spectroscopically confirmed members ) and an X-ray luminosity of ( 0.68 \pm 0.47 ) \times 10 ^ { 44 } ergs s ^ { -1 } in the [ 1-4 ] keV band . This optically selected cluster appears to be of richness class 3 and to follow the known L _ { X } - \sigma _ { v } relation for high redshift X-ray selected clusters . Using these data , we find that the halo occupation number for this cluster is only marginally consistent with what expected assuming a self-similar evolution of cluster scaling relations , suggesting perhaps a break of them at z \sim 1 . We also rule out a strong galaxy merging activity between z = 1 and today . Finally , we present a Bayesian approach to measuring cluster velocity dispersions and X-ray luminosities in the presence of a background : we critically reanalyze recent claims for X-ray underluminous clusters using these techniques and find that the clusters can be accommodated within the existing L _ { X } - \sigma _ { v } relation .