We present a detailed two-dimensional stellar dynamical analysis of a sample of 44 cosmological hydrodynamical simulations of individual central galaxies with stellar masses of 2 \times 10 ^ { 10 } M _ { \odot } \lesssim M _ { * } \lesssim 6 \times 10 ^ { 11 } M _ { \odot } .
Kinematic maps of the stellar line-of-sight velocity , velocity dispersion , and higher-order Gauss-Hermite moments h _ { 3 } and h _ { 4 } are constructed for each central galaxy and for the most massive satellites .
The amount of rotation is quantified using the \lambda _ { \mathrm { R } } -parameter .
The velocity , velocity dispersion , h _ { 3 } , and h _ { 4 } fields of the simulated galaxies show a diversity similar to observed kinematic maps of early-type galaxies in the ATLAS ^ { 3 D } survey .
This includes fast ( regular ) , slow , and misaligned rotation , hot spheroids with embedded cold disk components as well as galaxies with counter-rotating cores or central depressions in the velocity dispersion .
We link the present day kinematic properties to the individual cosmological formation histories of the galaxies .
In general , major galaxy mergers have a significant influence on the rotation properties resulting in both a spin-down as well as a spin-up of the merger remnant .
Lower mass galaxies with significant ( \gtrsim 18 per cent ) in-situ formation of stars since z \approx 2 , or with additional gas-rich major mergers - resulting in a spin-up - in their formation history , form elongated ( \epsilon \sim 0.45 ) fast rotators ( \lambda _ { \mathrm { R } } \sim 0.46 ) with a clear anti-correlation of h _ { 3 } and v / \sigma .
An additional formation path for fast rotators includes gas poor major mergers leading to a spin-up of the remnants ( \lambda _ { \mathrm { R } } \sim 0.43 ) .
This formation path does not result in anti-correlated h _ { 3 } and v / \sigma .
The formation histories of slow rotators can include late major mergers .
If the merger is gas-rich the remnant typically is a less flattened slow rotator with a central dip in the velocity dispersion .
If the merger is gas poor the remnant is very elongated ( \epsilon \sim 0.43 ) and slowly rotating ( \lambda _ { \mathrm { R } } \sim 0.11 ) .
The galaxies most consistent with the rare class of non-rotating round early-type galaxies grow by gas-poor minor mergers alone .
In general , more massive galaxies have less in-situ star formation since z \sim 2 , rotate slower and have older stellar populations .
We discuss general implications for the formation of fast and slowly rotating galaxies as well as the weaknesses and strengths of the underlying models .