Around 800-816 a religious sect in Abbasid Iran formed, known as the Khurramites. The Khurramites based their ideology largely on the ancient Mazdakite faith,...
The Manchurian operation was a strategic offensive operation by the Soviet Army and troops of the Mongolian People's Revolutionary Army during the Soviet-Japanese War...
In the Medieval period, every kingdom was at war, everyone was fighting against everyone and it was just a mess.
As technology developed a lot of things changed.