The founding fathers approved the draft of the Declaration of Independence on July 2, 1776, then signed it on July 4 - establishing that date as the United States' "birth" date.
But the declaration wasn't made public until July 8, when Lt. Col. John Nixon - the sheriff of Philadelphia - stood outside Independence Hall and read the document for the first time.
Today, his several times great-nephew - Gov. Jay Nixon - will repeat that role from 240 years ago in the 39th annual National Park Service ceremony recreating that first reading.
"I am truly excited," Nixon said at a Wednesday news conference, "to be able to stand where a relative of mine stood, but much more importantly where our country stands each year to officially mark the historic moment when the Declaration of Independence was read in public for the first time."
Nixon explained the first reading was delayed several days so the founding fathers - seen by the British as traitors - could get out of Philadelphia.
"They were really mad at the King," the governor noted. "When the Continental Congress on the 4th declared independence, it looked to be a little unsafe in the neighborhood with the British troops around.
"So they made the decision that the document would be read on the back steps of Independence Hall four days (later) - and they went back to their respective states, to begin what they knew would be the war of independence."
Reading it aloud can be difficult, the governor said, because "it wasn't written as a speech (but) as a legal document."
Nixon will dress in an 18th century period costume similar to what his relative wore. "I'm more concerned about the style of speaking than whether my leggings are going to look OK," Nixon said. "The honor and importance dramatically exceed the inconvenience."
The governor's family research shows the first Nixon landed in Philadelphia in 1687 on the "Endeavor."
After the Revolutionary War, the family relocated to New Orleans, then moved to East St. Louis, Illinois, "about the time of the Depression," Nixon said.
Nixon was born and raised in Jefferson County, south of St. Louis.
The governor said the family paperwork indicates Col. Nixon "was the brother of Jeremiah Nixon" from whom the governor is a direct descendant.
While his family's history is important, Nixon said his participation in the re-enactment is a symbol of a larger truth.
"Just because our family line runs to before 1776, we're all Americans," he said.
"If somebody got here last week folks who have chosen America recently or are about to choose to come to our country - they're every bit as American as we are.
"We are a land of immigrants - and we remain that."