It seems to me that the Middle-Ages/Renaissance observed a paradigm shift between the source of political power in Western Europe.
Indeed, in the High Middle-Ages, Kings were ruling surrounded by councelors who happened to be military leaders, warriors, or of military fame. For example, that page explains that
At the court Charlemagne relied upon aristocratic / military leaders as well as senior members of the clergy to ensure that all parts of his empire were run according to his wishes (Roberts, 1996 p. 110)
For the time being, I would ignore the presence of the Church.
Reading the novel Le Grand Coeur (French) about Jacques Coeur [1395-1456] and watching a related documentary, as well as reading the Wikipedia's page, all those sources seems to concur to a somewhat revolutionary approach of Charles VII of France by introducing merchants as "close" councillors. This, of course, happened after the demise of the French nobility in battles like Agincourt or Crecy.
Further in time, one can see that after the English Civil War and following Glorious Revolution of the 17th Century, the power struggle was between the King and the parliament. The 18th Century shows an increase in the role of the Parliament of britain in politics. In particular the House of Commons, composed of Land owners (more interested in economics than military). Walpole was noble, but his policies were
[...] for peace, lower taxes, growing exports [...]
At the end of the 18th Century, Washington was the first president of the USA and if he was of Noble ancestry, he didn't have a title himself. And following the French revolution, all government posts were occupied by non-noble members, most coming from merchant and/or land-owners families.
I thus see a trend shifting the political power from people whose primary concern were military to those mostly focusing on economy and finance.
I would like to know when did this shift in power paradigm occur?
From the Charles VII, Jacques Coeur part, it seems that it really started to happened at the end of the 100 years war, but I think it did not happened just yet.
Or am I reducing it to oversimplistic views?