The idea that losing teams were always killed is a misconception.

Evidence

It used to be thought that the losing team was always sacrificially slaughtered, and, though this did occasionally happen later, at the time of our belt we don’t know what lay in store for the losers. — Neil MacGregor, A History of the World in 100 Objects, 621

Categorization

• corroborated: 2 independent passages support this claim — Neil MacGregor, A History of the World in 100 Objects, 621