Ulysses and Marcus Macauley are Homer's brothers, and they each play important roles in shaping his life and journey of transformation. Ulysses is an active presence in Homer's life, sometimes causing trouble, often creating complications. Most often, however, Ulysses triggers his brother's affection.
Marcus, on the other hand, is for the most part physically absent, as the responsibility triggered by his absence is always in Homer's mind. Marcus triggers inspiration, awakens admiration, and at the end of the book, is a catalyst for redemption.
The Human Comedy