  Early-type galaxies (ETGs, i.e. elliptical and lenticular galaxies) differ in
their amount of rotational support -- some are purely supported by velocity
dispersion, while others show pronounced ordered rotation. Cosmological
hydrodynamical simulations show that the progenitors of all ETGs were first
rotating quickly, but then mergers decreased their rotational support. In the
presented work, we studied this process using an observational archaeological
approach. Namely, we inspected the correlations of 23 merger-sensitive
characteristics of local ETGs with a parameter quantifying the rotational
support. We used a volume-limited sample of local ETGs, that are not in galaxy
clusters, from the MATLAS survey. We found, for example, that slowly rotating
galaxies have tidal features and kinematically distinct components more often
and have lower metallicities. We sought for mutual interpretation of the
correlations among all 23 quantities, together with literature results on
high-redshift massive galaxies. There seems to be only one interpretation
possible: on average, ETGs lose their rotational support through multiple minor
wet mergers happening at the redshifts above about two.
