After months of debate and discussion through a hot Philadelphia summer, on Sept. 17, 1787, the newly proposed Constitution of the United States of America was signed by 38 of the 41 delegates still at the Constitutional Convention.

Before the signing, the document was read, and a debate ensued about whether the document would be signed. A speech written by Benjamin Franklin was read, and his motion that the delegates sign was approved. Three dissenters (Elbridge Gerry, George Mason, and Edmund Randolph) declined to sign.

So it makes sense that Constitution Day would be observed on Sept. 17 each year. That practice as a matter of U.S. law, however, only dates back to 2004. As part of an omnibus bill, the federal holiday known as “Citizenship Day” became “Constitution and Citizenship Day.”

Citizenship Day had been observed since 1952, when Congress created it “in commemoration of the formation and signing, on September 17, 1787, of the Constitution of the United States and in recognition of all who, by coming of age or by naturalization have attained the status of citizenship.” The designation was accompanied by an invitation to “the people of the United States to observe the day in schools and churches, or other suitable places, with appropriate ceremonies.”

The 1952 resolution noted that Citizenship Day replaced a holiday called “I Am an American Citizen Day.”

A Time magazine story explains the origin of that commemoration:

David F. Schmitz, a professor of History at Whitman College, credits a Polish refugee for organizing the first “I Am An American Day” celebration on May 31, 1938, in Huntington, N.Y. on Long Island. Bronislava du Brissac, better known in the United States as Mrs. Paul d’Otrenge Seghers, fled Poland after the 1917 Russian Revolution, and she and her husband had a farm on the North Shore. “She had achieved the American Dream as a refugee immigrant to the U.S., to now being part of a wealthy, successful family,” says Schmitz. She organized “I Am an American Day” through the Helios Foundation, a group she founded that organized charitable activities that benefited the larger community.

The next year, newspaperman William Randolph Hearst promoted the idea of “I Am an American” events, which then caught on in other cities. The popularity of the idea can be attributed in part to the rise of immigration at this time when many were fleeing war-torn Europe. In 1940, President Franklin Roosevelt signed a congressional joint resolution designating the third Sunday of May as I Am an American Day.

In the same spirit, a few months later, Albert Einstein, as a newly naturalized citizen, appeared on a special radio series called, “I’m an American” sponsored by the Immigration and Nationalization Service. A 1944 film called “I Am an American” focused on the contributions immigrants made to the United States – and unsurprisingly, given the time, their military contributions

It seems appropriate that the history of the commemoration of the Constitution would be linked to appreciation for immigrants to the United States whose identity as Americans was formed by the great charter of the new nation. That charter, formed in the remarkable 1787 convention, still is a uniting force for citizens and a beacon of self-determination for the world.