During the period of disunion what happened when different cultures came in contact with each other?

Please clarify what you mean by "period of disunion" and which cultures you are referring to.

For example, are you thinking about:

* The Period of Disunion in Chinese history (220-589 AD): If so, you'd be talking about the interactions of various Chinese dynasties and kingdoms with each other, as well as with other cultures like the Xiongnu, Xianbei, and other nomadic groups.

* The breakup of the Roman Empire (395 AD onward): This would involve interactions of Romans with Germanic tribes, Persians, and other groups in the Mediterranean and Europe.

* Other historical periods of fragmentation or disunion in other parts of the world?

Once you provide more context, I can provide a more specific and helpful response.