Roman empire vs Mongol empire vs Russian empire

[Sarmatian]

Because of taking Persian and Chinese engineers.

And how did they captured Persian and Chinese fortified cities before taking Persian and Chinese engineers exactly?

[Mingle]

And how did they captured Persian and Chinese fortified cities before taking Persian and Chinese engineers exactly?

The Mongols first defeated the Western Xia and then kept gaining defectors from the other Chinese entities which were in civil war with each other, particularly the Jin and Song. Enough that they created a whole army out of Han defectors called the "Newly Submitted Army". The biggest weapon for conquering fortified cities was the counterweight trebuchet which was developed by Arab engineers.

They had a thousand siege engineers from northern China when conquering West Asia. They got Persian engineers from conquering Persia.

By the way, I'm not trying to downplay the Mongols but you asked how they took down fortified cities so I gave you the answer.

[joewhite]

mongols reached the max size ever

[Melki]

One thing is sure, if the Mongols never existed, Kyiv would have remained the capital city of the Russian Federation until now, Ukrainian language would be spoken throughout Eurasia all the way to Vladivostok. Gogol and Pushkin would have written their novels and gained world fame in their own plain Slavic, no Finno-Ugric influenced language, and a Hohol leader would have replaced Putin in a huge blue and yellow Eurasian state.

[renaissance12]

Rome Caesar Russia Tzar .......Mongol

( in simple words... what is the contribution to civilization of the mongols ?.. )