PHILADELPHIA (AP) – A letter from US President Abraham Lincoln guaranteeing Frederick Douglass' safety, Malcolm X's Quran and diary, and Muhammad Ali's robe from the "Rumble in the Jungle" are among the artefacts in a new touring black history exhibition.

"America I AM: The African American Imprint" will open at the National Constitution Center in Philadelphia on January 15, Martin Luther King, Jr.'s birthday. Presented by TV personality Tavis Smiley, the show includes more than 200 items from every period of US history.

It will travel to nine more cities over the next four years.

Other artefacts on display include the key to King's jail cell and the stool on which he sat in Birmingham, Alabama, where he composed his famous "Letter From the Birmingham Jail"; the "Doors of No Return", through which Africans trod before boarding slave ships in what is now Ghana; the desk that literary pioneer Phyllis Wheatley used to write "Poems on Various Subjects, Religious and Moral", which was published in 1773; and Mary McLeod Bethune's walking cane, which once belonged to President Franklin Delano Roosevelt and was given to Bethune by former first lady Eleanor Roosevelt.

Many of the individual artifacts have been previously seen in various museums, libraries or personal collections, but "America I AM" is a rare opportunity to see many important objects in one place, said John Fleming, executive producer of the exhibition and director emeritus at the Cincinnati Museum Center.

Fleming said he hopes visitors will gain a new understanding of what it means to be an American.

The exhibition also includes an interactive component that encourages visitors to leave video messages. Organisers hope this will grow into the largest recorded oral history project in US history.

Tickets went on sale yesterday at www.AmericaIAm.org.