The Norman invasion in the year 1066 is considered to be very significant because it changed England in many ways. This linked England even more with the continent of Europe. It created one of the most strong monarchies in Europe and resulted in the impact and hold of Scandinavian to weaken a lot. This invasion changed the English traditions and language and there were some influence of language of France and it's culture.
Hayek believed the economy too complicated to think in terms of aggregates. This is the foundation of monetarism theory. He believed that people are unpredictable in their choices. Consequently, expansionary policy was potent because it could potentially lead to inflation and affect individual choices.