Shakespeare

This is the first of four instances of "Ulysses" in the text , marking this passage as notable. The character Ulysses appears in Shakespeare's Troilus and Cressida, Dante's Inferno, and as Odysseus in Homer's Iliad and Odyssey. The character's "appearance" in Joyce appears to be part of the latter's 3+1 pattern: or why the number "four" is significant in Joyce's book.

From the Scottish play, description of the castle at Inverness. The birds love it. "Coign" = corner; viz., a useful corner. http://shakespeare.mit.edu/macbeth/macbeth.1.6.html

Julius Caeser allusion.