The following period, when quarks became confined within hadrons, is known as the hadron epoch.

It started roughly 1 second after the Big Bang, after the majority of hadrons and anti-hadrons annihilated each other at the end of the hadron epoch.

In physical cosmology, the hadron epoch was the period in the evolution of the early universe during which the mass of the Universe was dominated by hadrons.

The majority of hadrons and anti-hadrons annihilate each other at the end of the hadron epoch, leaving leptons and anti-leptons dominating the mass of the universe.