Greek mythology is a treasure trove of allegorical tales and colorful characters. Thackeray makes good use of a few of these characters in order to better highlight certain qualities of his own characters. He derives his comparisons from stories told by Aeschylus, the Greek tragedian, and Ovid, the Roman poet.
Becky famously and scandalously plays Clytemnestra in charades. In ancient Greek mythology, Clytemnestra was the sister of Helen and the wife of King Agamemnon. She was upset with her husband for the murder of their daughter, Iphigenia, and for his absence during the Trojan War, so she conspired with her lover, Aegisthus, to kill him and his new mistress, Cassandra. The connection between Becky and Clytemnestra is clear; both are femmes fatales of a sort, and both deceive and destroy the men in their lives.
Thackeray notes that in Chapter 23, there is a loud ticking of an Iphigenia clock in the Osborne house. This is the chapter in which Old Osborne is making plans for his daughters, plans that don't have anything to do with what they actually want.
Iphigenia is the daughter of Agamemnon and Clytemnestra. Agamemnon is trying to get to war with Troy, to help his brother Menelaus get his wife back, but the winds will not blow to move the ships. A priest tells Agamemnon that in order to get the winds, he must sacrifice his daughter. Agamemnon concedes.
Adonis is a beautiful youth with whom Venus, the goddess of love, falls in love. Jos' valet, Isidor, imagines himself as Adonis when he is fantasizing about all the finery he is going to steal from his master.