The four developments which were made under Mongol rule during the pax Mongolica are:
They established of a postal system
The spread of weapons that used gunpowder
The extension of the grand canal in China
The invention of new medicines
The Pax Mongolica refers to the stabilizing impacts of the conquests of the Mongol Empire on the social, cultural and economic life of the citizens of the vast Eurasian territory that the Mongols conquered in the 13th and 14th centuries.
