The “huge key" that locks the strong exterior door of the tower is mentioned eight times in Telemachus. Stephen is keenly aware that Mulligan “wants that key,” and events prove him right: Mulligan asks for the key, and much later in the book he gives Stephen the slip and goes home to Sandycove without him. Stephen thinks of Mulligan at the end of Telemachus as a “Usurper," and in Proteus he thinks, "He has the key. I will not sleep there when this night comes." Giving up the key equates to homelessness for Stephen. This motif will eventually reach out to encompass Bloom and Ireland.

JH 2011

Source unknown.