King spoke at Hofstra the year after he won the Nobel Peace Prize and just months after "Bloody Sunday" in Selma, Alabama.
The letter in Wichita shows an early draft that might have informed some of the civil rights leader's most famous speeches.
A large crowd turned up in Denver on Monday to celebrate the legacy of Martin Luther King Jr.
Martin Luther King Jr.'s iconic 1963 "I Have a Dream" speech is well known, but there are several other key speeches that also resonate as historical signposts of the Civil Rights Movement.