Nawadaha
At some level, Henry W. Longfellow probably knew he wasn't well qualified to talk about Native American legends. So he did a clever thing. He wrote an introduction to The Song of Hiawatha where he claims that the entire long poem was something he actually heard being sung by a travelling Native American musician named Nawadaha, as we read:
There he sang of Hiawatha,
Sang the song of Hiawatha,
Sang his wondrous birth and being,
How he prayed and how he fasted. (I.70-73)
What Longfellow does here is keep himself at arm's length from everything he writes in the poem. By having this fictional minstrel tell the story, instead of himself, Longfellow gives himself the ability to take all the credit for the poem while having an excuse if people don't like it. He has the chance to say, "Hey, don't blame me. I'm just writing down what Nawadaha was singing." It's especially important to remember that the speaker of this poem is a Native American character because it shows that Longfellow was savvy enough to realize that an old bearded white man like himself wouldn't be a great spokesperson for the indigenous peoples of North America.