  This paper presents ASCA (July 1997), XMM-Newton (December 2000) and BeppoSAX
(January 2001) observations of the Piccinotti Seyfert 1 galaxy ESO198-G24. The
BeppoSAX 0.1-200 keV spectrum exhibits reprocessing features, probably produced
by an X-ray illuminated, relativistic accretion disk subtending a solid angle
\~2 pi. During the XMM-Newton observation the fluorescent iron K-alpha line
profile (centroid energy E~6.4 keV) was broad and twice as bright as in the
BeppoSAX observation. An additional emission feature (E~5.7 keV), detected at
the 96.3% confidence level, may be part of a relativistic, double-peaked
profile. By contrast, in the earlier ASCA observation the line profile is
dominated by a remarkably narrow "core" (intrinsic width <50 eV). If this
component is produced by reflection off the inner surface of a molecular torus,
its large Equivalent Width (~300 eV) most likely represents the "echo" of a
previously brighter flux state, in agreement with the dynamical range covered
by the historical X-ray light curve in ESO198-G24.
