  We present a chronology of the formation and early evolution of the Oort
cloud by simulations. These simulations start with the Solar System being born
with planets and asteroids in a stellar cluster orbiting the Galactic center.
Upon ejection from its birth environment, we continue to follow the evolution
of the Solar System while it navigates the Galaxy as an isolated planetary
system. We conclude that the range in semi-major axis between 100au and several
10$^3$\,au still bears the signatures of the Sun being born in a
1000MSun/pc$^3$ star cluster, and that most of the outer Oort cloud formed
after the Solar System was ejected. The ejection of the Solar System, we argue,
happened between 20Myr and 50Myr after its birth. Trailing and leading trails
of asteroids and comets along the Sun's orbit in the Galactic potential are the
by-product of the formation of the Oort cloud. These arms are composed of
material that became unbound from the Solar System when the Oort cloud formed.
Today, the bulk of the material in the Oort cloud ($\sim 70$\%) originates from
the region in the circumstellar disk that was located between $\sim 15$\,au and
$\sim 35$\,au, near the current location of the ice giants and the Centaur
family of asteroids. According to our simulations, this population is
eradicated if the ice-giant planets are born in orbital resonance. Planet
migration or chaotic orbital reorganization occurring while the Solar System is
still a cluster member is, according to our model, inconsistent with the
presence of the Oort cloud. About half the inner Oort cloud, between 100 and
$10^4$\,au, and a quarter of the material in the outer Oort cloud, $\apgt
10^4$\,au, could be non-native to the Solar System but was captured from
free-floating debris in the cluster or from the circumstellar disk of other
stars in the birth cluster.
