What are the two main ways of communication between ancient eastern and western civilizations?

In ancient times, there were two main ways of communication between eastern and western civilizations: violent conflict and peaceful communication.

There are two ways of communication of human civilization: violent conflict and peaceful communication. Violent conflict mainly refers to war. War is a continuation of politics, and it is bloody politics. War is full of violence, while objectively spreading culture. In ancient times, there were contradictions and collisions between powerful countries and weak countries between different civilizations and different regions. In this process, accompanied by violence, slavery and oppression, it also objectively led to the exchange and integration between different cultures. As Marx pointed out: "Every progress in human history is often at the expense of other small and weak ethnic groups".