On this date in 1963, the Rev. Dr. Martin Luther King Jr. delivered one of the most iconic speeches of the last century on the steps of the Lincoln Memorial in Washington, D.C.

Here are some things you may not have known about the “I Have a Dream” speech:

The full name of the event King was speaking at was the March on Washington for Jobs and Freedom. Initially it was organized by A. Phillip Randolph and Bayard Rustin, who envisioned a two-day sit-in and protest with a rally at the Lincoln Memorial. Later a group of civil-rights leaders called the Big Six took over organizing and funding of the event.

The night before the march, as one of the Big Six, King had been so busy helping organize the event that he hadn’t settled on what he planned to say the next day. The speech has its roots in several other of King’s speeches, including one he gave in Detroit in June 1963. Toward the end of the speech, at the urging of gospel singer Mahalia Jackson, King broke from his prepared remarks and began speaking extemporaneously. This is the part of the speech that is most famous today.

In the speech, King didn’t use the word “dream” until more than 11 minutes into the 16-minute address. King then proceeds to use the phrase “I Have a Dream” or a variation eight times in the final third of the speech.

The repeated use of a word or term for emphasis is a rhetorical device known as anaphora. It also adds rhythm to a work and helps make the text easier to remember.

Our question, who was president of the United States during the March on Washington?