Which societies gained the most as a result of the Mongol period?

Negative effects of the Mongol Empire's expansion into Western europe, East Asia, include the wiping out of people that resisted given the violent nature of their invasions.

Positive effects include a century of peace those under under Mongol rule. This stability allowed for the reopening of the Silk Road trading routes between China and Europe, increasing cultural exchange and wealth all along the trade paths including Western Africa, East Asia and Europe.