  We reconstruct the star formation history of the Sco-Cen OB association using
a novel high-resolution age map of the region. We develop an approach to
produce robust ages for Sco-Cen's recently identified 37 stellar clusters using
the SigMA algorithm. The Sco-Cen star formation timeline reveals four periods
of enhanced star formation activity, or bursts, remarkably separated by about 5
Myr. Of these, the second burst, which occurred about 15 million years ago, is
by far the dominant, and most of Sco-Cen's stars and clusters were in place by
the end of this burst. The formation of stars and clusters in Sco-Cen is
correlated but not linearly, implying that more stars were formed per cluster
during the peak of the star formation rate. Most of the clusters that are large
enough to have supernova precursors were formed during the 15 Myr period. Star
and cluster formation activity has been continuously declining since then. We
have clear evidence that Sco-Cen formed from the inside out and contains 100-pc
long chains of contiguous clusters exhibiting well-defined age gradients, from
massive older clusters to smaller young clusters. These observables suggest an
important role for feedback in forming about half of Sco-Cen stars, although
follow-up work is needed to quantify this statement. Finally, we confirm that
the Upper-Sco age controversy discussed in the literature during the last
decades is solved: the nine clusters previously lumped together as Upper-Sco, a
benchmark region for planet formation studies, exhibit a wide range of ages
from 3 to 19 Myr.
