The office of "President of the United States" was created in the Constitution of 1787. Prior to that, it did not exist. There were several people who served as the presiding officer of the Continental Congress and the Congress of the Confederation, but that did not make them the President of the United States.
Thanks for your comment. I can see both sides of the argument. However, from the Articles:
"The United States in Congress assembled shall have authority to appoint a committee, to sit in the recess of Congress, to be denominated 'A Committee of the States', and to consist of one delegate from each State; and to appoint such other committees and civil officers as may be necessary for managing the general affairs of the United States under their direction -- to appoint one of their members to preside, provided that no person be allowed to serve in the office of president more than one year in any term of three years"
I gather that Hanson's correct title was the "President of the United States in Congress Assembled". It is a nit in my opinion not to give him the recognition he deserves. He had the power to correspond and negotiate with foreign governments and was given a household and servants. Hanson in fact formed the first departments to run the government, formed the first cabinet, established the first post office, and had Benjamin Franklin as his Secretary of State, though I'm not sure what Franklin's office was called back then.
The powers of the president were expanded under the 1787 Constitution. Washington remains the first president under the Constitution. Washington reportedly congratulated Hanson in a letter upon Hanson's selection as president, saying, "I congratulate your excellency on your appointment to fill the most important seat in the United States."