Each of the three mirror modules of the XMM Wolter-I-type telescope is composed of 58 nested mirror shells. The smallest gap between two adjacent mirror shells measures only 1.6 mm. The fixation and alignment concept has been qualified with the Optical Demonstration Model 0DM, which consists of four CFRP mirrors. It has the same entrance diameter (700 mm) as the flight model. The 3D topology of the mirrors was determined for spatial wavelengths ranging from 3 ,sm to 550 mm by three measuring devices. The optical quality of the mirror shells as a function of x-ray energy was predicted by a code developed at Zeiss. During integration roundness and alignment of the mirrors were monitored by a full-aperture Hartmann-type test with visible light. The entire model and single mirrors have been x-ray tested at the MPE long beam facility at photon energies up to 8 KeV. The results of x-ray tests and performance predictions are compared and discussed.