When Martin Luther King Jr. made his most famous speech during the Great March on Washington in 1963, Barack Hussein Obama was 2 years and 24 days old.

Obama was only 6 when King was assassinated in 1968.

So, except through reading history, and perhaps taking some black studies classes, the man who would become the first black president of the United States didn't know King like those born a generation earlier.

Some have argued that because of the time and place of his birth (in Hawaii in 1961), Obama never experienced the overt, de jure discrimination that King fought against. And besides, some black elitists said during the 2008 presidential campaign, Obama didn't have "slave ancestry" because he's the son of a white Kansan mother and black Kenyan father.

That observation was considered by some a kind of ridiculous "evidence" that Obama was not a "true" black American. I won't dignify the assertion by discussing the degree of one's blackness, whether someone is more black than somebody else.

As I've pointed out before, African-Americans didn't define black when it came to race in America; it was white people who came up with the "one-drop" rule: One drop of black blood, no matter how white you looked, made you black.

But, let's leave that alone for now.

Despite the gap in their ages and the generational and geographical differences that helped define Obama and King, their legacies are inextricably tied, albeit the president's legacy is still in the making.

Since Obama's nomination in 2008, there have been some momentous instances that, though coincidental, have connected the two men -- happenstance that some of us have seen as divine providence.

Consider Obama's acceptance speech for his party's nomination, made before 84,000 people in a Denver football stadium. I was not the only one to note that it occurred on the 45th anniversary of King's address telling America about a dream he had.

Then came Obama's historic election, which had many in the country wondering if King could have imagined such a day. Ironically, Robert F. Kennedy had predicted (a couple of months before Obama's birth) "that in the next 30 or 40 years, a Negro can also achieve the same position that my brother has as President of the United States, certainly within that period of time."

When the president was inaugurated on that cold day in 2009, with two million proud observers in attendance -- the largest gathering ever in the nation's capital -- it reminded many people of that very hot day in August when hundreds of thousands came to Washington to demonstrate for "jobs and freedom."

And how surreal was it that when the Martin Luther King, Jr. National Memorial, which had been years in the making, was finally dedicated on the National Mall in 2011, it was America's first black president who would make the dedicatory speech?

Now comes Obama's second inauguration. Keep in mind that until the 20th Amendment was ratified in 1933, the term of the new president began in March. Passage of the amendment moved the date up to Jan. 20.

Since Franklin Roosevelt's second term, all presidents except two have had their public inaugurations on Jan. 20. The exceptions were Dwight Eisenhower in 1957 and Ronald Reagan in 1985, because Jan. 20 fell on a Sunday those two years, moving the inaugurations to Jan. 21.

This is another year of the exception. Because Jan. 20 is Sunday, Barack Obama's second public inauguration will take place on Monday the 21st.

That's the day the nation has set aside to celebrate Martin Luther King's birthday.

Coincidence or providence?