What changes did Islamic expansion generate in those societies that encountered it, and how was Islam itself transformed by those encounters

Answer: After the unification of the Arab tribes, Islam expanded in all directions. Within a few decades, it occupied an area of land only comparable to the Roman Empire in its heyday. It would soon assume the role of commercial liaison between economically important areas of the world then: in Europe, Africa and Asia. The military progress achieved by the Muslims allowed them to isolate Europe, blocking trade especially through control of the Mediterranean Sea. For many historians, this has accentuated a trend that had existed since the 5th century, focused on agrarian life, and which would lead Europe to feudalism.

The Islam changed because of these encounters, with technology, some traditions and religions were swept away or changed.