One of the most consumed commodities in the world is oil, and as is well known, the price is set by OPEC in US dollars, with this organization being strongly influenced by Saudi Arabia.
It is therefore towards Riyadh that we must look in order to understand the workings of the petrodollar. After the dollar was withdrawn from the gold standard, Washington made an arrangement with Riyadh to price oil solely in dollars. In return, the Saudis received protection and were granted a free hand in the region. This decision forced the rest of the world to hold a high amount of US dollars in their currency reserves, requiring the purchase of US treasuries. The relationship between the US dollar and oil breathed new life to this currency, placing it at the centre of the global financial and economic system. This privileged role enjoyed by the dollar allowed the United States to finance its economy through the simple process of printing its fiat currency, relying on its credibility and supported by the petrodollar that required other countries to store reserves of US treasuries in their basket of currencies.