Who or what is overrated?
Which prominent empire or figure has been overhyped?
I’d say the Mongols fit the bill here.
Led by Genghis Khan, the Mongols united and rose to conquer much of Asia and Eastern Europe. In the 13th-14th centuries, they formed the biggest empire known at that point. In terms of land area, they were larger than the Roman Empire, Alexander the Great’s Greek conquests, and all of the Chinese dynasties up to that point. This was superseded by the British Empire, which reached its territorial height in the early 1920s.
Why was the Mongol Empire overrated?
Mainly due to:
Conquering weak powers
The Chinese dynasties despite having immense manpower were not very strong overall. The Mongols’ cavalry-based armies were something they and others couldn’t handle. However, China was not militarily prepared for this war, which they eventually lost, leading to the formation of the Yuan Dynasty.
The Abbassid Caliphate also wasn’t strong, and neither were the Kievan Rus’.
It is very easy to conquer weaker powers, with unique or at least untried and unfamiliar tactics.
Lack of legacy
The Mongols’ main legacy is stories of their conquests, as well as how well they facilitated trade in their vast empire.
However, if one looks now at the lands the Mongols ruled, not many if any speak Mongolian or are influenced by Mongolian law, customs, religion, etc.
This is in direct contrast with Rome, Britain, Spain, etc. Rome has influenced European culture in many ways, from great buildings and works to the calendar we use, languages such as French, Italian, Spanish, and Portuguese, and even the titles of the former Russian and German Emperors (tsar and Kaiser, after Caesar). Britain made the English language the general lingua franca and language of business, and many countries around the world have it as an official language. Much of the world’s major technological and cultural norms today were created in Britain.
The Mongols in contrast don’t hold a similar legacy.

Yes, they conquered an immense area. However, they didn’t achieve much other than this.
Their legacy thus cannot equate to other great empires of history.
Great works
Rome created aqueducts and roads which still exist.
Britain made infrastructure that still lasts today. Indian railways, bridges in Africa, and the railway tracks and bridges of Britain today are Victorian in form.
The Mongols didn’t achieve much of note, by comparison.
There are not many Mongol-made structures that signify their power, prestige, or standing.

What makes Rome, Britain, Spain, Portugal, etc. amongst the greatest empires is their holistic influence and scope. They didn’t just conquer vast lands, but they instilled and spread culture to widespread places. The Age of Discovery led by Portugal led to the Colombian exchange and access to foreign foodstuffs that today are normal to many - bananas, tomatoes, coffee, tea, and chocolate are examples of this. Prior to the early modern period, these were confined to their various endemic geographical regions.
Local powers in Africa such as the Asante and Zulu both represent today the values established by their respective founders, Osei Tutu I and Shaka.
These points aren’t to denigrate the Mongols, and they of course had a mighty army that many of the time couldn’t handle. However, I believe if accounting for their achievements, they don’t measure against other noted empires in history.