Ancient China suffered from raids from the Xiongnu Confederation of modern-day Mongolia. At first, the Chinese tried defensive tactics such as building the Great Wall and ~~paying tribute~~ donating gifts. But the raids continued, so in 119 BCE the Han Dynasty sent an army into Mongolia. The Chinese army was much smaller, but better trained and much better supplied. In three battles they pretty much annihilated the Xiongnu army, with the survivors splitting into smaller groups (and some even becoming Han vassals).

Some Xiongnu tribes retreated north and west into modern-day Siberia and south Russia, pushing the residents westward. They, in turn, moved into eastern Europe and Germany. This pushed the Visigoths of Germany southwards, where they sacked Rome in 410 CE. While Rome was no longer the capital of the Roman Empire, it was still a major cultural and economic centre, and its fall sent shockwaves across Europe.

The migrations also caused the collapse of the Burgundian Kingdom (in modern-day Rhineland, not modern-day Burgundy) at the hands of the Huns (and their Roman allies), which forms the backdrop of the German epic the Nibelungenlied (not to be confused with Wagner's Ring of the Nibelung, which, despite sharing most characters, borrows heavily from the Norse version of the legend and Wagner's political (socialist) and religious (Buddhist) beliefs).

Image description: A picture of Jesus floating in space and facing the camera with the earth in the backround, there are onions badly edited into his outstretched hands and an impact font caption that reads "what if Pliny the Elder said bite this onions"

If the south had problems with lack of infrastructure, why didn't they just use the underground railroad?

cross-posted from: https://monyet.cc/post/418238

Related to the Bunga Mas^1:

According to a Kedah source, the first time a bunga mas was sent, it was sent as a toy for a new-born Thai prince who was the grandson of Sultan of Kedah himself since his kin, a princess was married to the Thai king^1.

This then set the precedence of Malay Sultans being "required" one way or another to send Bunga Mas to Siam. The culmination of the meme is the Siamese invasion of Kedah in 1821^2 partly due to the Sultan ceasing sending bunga mas, making Kedah Sultanate, the progenitor of the practice, existn't for a time.

* This is a Malay expression meaning paying interests. The principal is the pokok (tree) and the interest is the bunga (blossoms).