TTC A Brief History of the World: lecture 4, The Classical Period in World History
Выражение встречается в следующем контексте: "[...] The classical period gains coherence from two simple developments. A. These societies were territorially much larger than their river valley predecessors. B.With the partial exception of the Mediterranean, the achievements ofthese classical civilizations represented fairly durable expansions of their territories."

Не могу сообразить, как лучше передать "gain coherence".

Спасибо