Reading the Song of Susannah. Bought the Song of Roland. Looked up the Song of Roland on E2. The Song of Roland is only tangentially related to Childe Roland to the Dark Tower Came. Said poem is based off of Shakespeare's line in King Lear,
"Child Roland to the dark tower came,
His word was still, "Fie, fo, and fum;
I smell the blood of a British man."
Which referenced not the son of Charlemagne, but probably a Scottish hero named Rowland.
Now, of course I am also doing Linear Algebra at the same time, looking up orthonormal basis on the Internet. And, of course, Todd Rowland wrote the information on MathWorld. http://mathworld.wolfram.com/OrthonormalBasis.html