As in any system, accumulation patterns of different nations were created from different monetary theories.Foreign currencies exchange was one of bases from which countries started to build an economic model.
Before the First World War the foreign currency exchange was done taking as base the pound value that was the foreign currency with which world commerce was working.
Before Bretton Woods, gold standard was the one that used to regulate the foreign currencies exchange, once the arrangement was signed in 1944, national currencies exchange was fixed according to the dollar, fixing the gold ounce price in 35 american dollars.
Since that moment, the bills issue was limited to the amount of gold reserves of each nation. That’s how the United States started to have the biggest reserves in the world and foreign currencies exchanges started to depend on the United States.
In 1971 economy changed as president Nixon announced that he would let dollar float free. Since 1973 new rules started to be used and foreign currencies exchange started to be regulated by the supply and demand market forces, giving world economy more freedom and free currency flotation.

More that thirty years ago, Nixon decided not to have any more the convertible currency Dollar-Gold and made the dollar has no standard to support it. Since then, the dollar became a paper with no support.
Since the appearance of the euro, in the year 2002, it hasn’t stopped gaining ground, the increase of the value of the euro in front of the actual dollar is indicating that the cost of life is even higher in Europe. Actually the power of the actual dollar is based on the militar power and on the ability of the United Stated of issueing reference currency to any international transaction.
The actual dollar has been devaluated in the last years regarding to other international foreign currencies. American authorities saw what could happen to the dollar in 2001, after the attack to the Twin Towers when the war against the Middle East started. In 2003 Jeffrey Frankel (Economist and professor of the Harvard University, and ex adviser of the ex president Bill Clinton), foreseeing what could happen to the actual dollar decided to fix the weak dollar to the crude value.
Basically the proposal was to fix foreign currencies, in this case to the actual dollar with some product (exports), or crude materials in this case crude. This proposal is not very different to what happened in 1944 when Bretton Woods arrangement established the Gold Standard, until August 15th 1971, date on which the dollar began to float free.
If they carry out the idea of Jeffrey Frankel, they would give the actual dollar a support more than enought for the American currency to become appreciated as the crude price will continue raising in these last years.

The pound was the most popular forreign currency until 1945. Until that date the international trade was regulated by this currency value, where all the transactions have to be through England and it was done with that currency.
The end of the Second World War was the end of british control and so did the pound as reference currency. Bretton Woods arrangement established that American Dollar would be the currency able to regulate all the commercial transactions in the world.
Actually, the pound is falling its value. Euro introduction in 1999 made the pound lose ground in the principal economic decisions of the world. This situation has made British financial institutions look for a solution for this problem, and one of the measures that banks have taken is to reduce the cost of interest rates to the level of the European Union, and so, be able to compete with the raising Euro. In some years it would be very different for the pound to be as it used to be some years ago.