The Schlieffen Plan was created by General Count Alfred von Schlieffen in December 1905. The Schlieffen Plan was the operational plan for a designated attack on France once Russia, in response to international tension, had started to mobilise her forces near the German border
They were. Around that time there were issues between Russian Orthodox Christians and Muslims who were found in their south because of the Ottoman Empire. There were also insurgencies of Orthodox Christians in Ottoman controlled territories in former Slav areas.
I'd say the Dark Ages is the best description. Rome fell in 1000 C.E. and after that, everything got worse and worse. The Black Plague was also in the 1340s. No guarantees, feudalism was also around during those years.
The 7th and the 8th century was like 1st millieunum