  We numerically integrate the equations of motion of the Sun in Galactocentric
Cartesian rectangular coordinates for -4.5 Gyr <= t <= 0 in Newtonian mechanics
with two different models for the Cold Dark Matter (CDM) halo, in MOdified
Newtonian Dynamics (MOND) and in MOdified Gravity (MOG) without resorting to
CDM. The initial conditions used come from the latest kinematical determination
of the 3D Sun's motion in the Milky Way (MW) by assuming for the rotation speed
of the Local Standard of Rest (LSR) the recent value \Theta_0=268 km s^-1 and
the IAU recommended value \Theta_0=220 km s^-1; the Sun is assumed located at
8.5 kpc from the Galactic Center (GC).
  For \Theta_0=268 km s^-1 the birth of the Sun, 4.5 Gyr ago, would have
occurred at large Galactocentric distances (12-27 kpc depending on the model
used), while for \Theta_0=220 km s^-1 it would have occurred at about 8.8-9.3
kpc for almost all the models used. The integrated trajectories are far from
being circular, especially for \Theta_0=268 km s^-1, and differ each other with
the CDM models yielding the widest spatial extensions for the Sun's orbital
path.
