  We report on a medium deep XMM-Newton survey of the Marano Field and optical
follow-up observations. The mosaicked XMM-Newton pointings in this optical
quasar survey field cover 0.6 square degree with a total of 120 ksec good
observation time. We detected 328 X-ray sources in total. The turnover flux of
our sample is f~5x10^(-15) erg/cm^2/s in the 0.2-10 keV band. With VLT FORS1
and FORS2 spectroscopy we classified 96 new X-ray counterparts. The central
0.28 square degree, where detailed optical follow-up observations were
performed, contain 170 X-ray sources (detection likelihood ML>10), out of which
48 had already been detected by ROSAT. In this region we recover 23 out of 29
optically selected quasars. With a total of 110 classifications in our core
sample we reach a completeness of ~65%. About one third of the XMM-Newton
sources is classified as type II AGN with redshifts mostly below 1.0.
Furthermore, we detect five high redshift type II AGN (2.2<z<2.8). The optical
and X-ray colors of the core sample indicate that most of the still
unidentified X-ray sources are likely to be type II AGN. We calculate absorbing
column densities and show that the ratio of absorbed to unabsorbed objects is
significantly higher for type II AGN than for type I AGN. Nevertheless, we find
a few unabsorbed type II AGN. The X-ray hardness ratios of some high redshift
type I AGN also give an indication of heavy absorption. However, none of these
type I objects is bright enough for spectral extraction and detailed model
fitting. Furthermore, we classified three X-ray bright optically normal
galaxies (XBONGs) as counterparts. They show properties similar to type II AGN,
probably harbouring an active nucleus.
