The most common organism in spinal infection is from the bacteria Staphylococcus aureus which typically exists on human skin, followed by Escherichia coli. Most spine infections occur in the lumbar spine because of the blood supply to this region of the spine.
Feudalism, a system of political and military relationships, evolved in western Europe. The feudal system was a simple but effective means of medieval government in which the king rented land to barons, who provided him knights and taxes
Although feudalism develops as early as the 8th century, under the Carolingian dynasty, it does not prevail widely in Europe until the 10th century - by which time virtually the entire continent is Christian. For the next 500 years, great accumulations of power and landed wealth pass between a few favoured players as if in a vast board game.