War between the Huns and the Han also lead to the opening of the Silk Route. In search of allies against the Huns, the Hans were looking for the Yuezhi people, who left the Gansu after being forced out by the Hans. The Yuezhi is actually an Indo-European people, and they would settle somewhere in Pakistan and Afghanistan to create the Kushan Empire.
In the attempt to establish contact with Yuezhi, which succeeded by the way, the route to the West was discovered, and this led to the Silk Road. And through this road, the Parthians got rich playing in between selling Chinese silk to the Romans and selling the Hans the Persian horses in exchange.
The large Persian breeds amounted to a revolution in cavalry. Previous horses are too small to mount a heavy, armored and well armed rider, but these horses can. With that, the Han created an autonomous elite heavy cavalry arm that would rout the Huns, who although great horse riders themselves, are saddling on smaller ponies.
As for the Romans, their addiction to the silk "crack", may have a role in dooming their empire as they expend too much on this luxury.