Katherine is Mathias’s mother, and she serves to personify vengeance and anti-Semitic hate. When Katherine catches Mathias talking to Barabas, she forbids her son to converse with a Jew, and even though Mathias admits he is in love with Abigail, he is hesitant to act on his feelings for fear his mother won’t approve. When Mathias is killed in the duel with Lodowick, Katherine, like Ferneze, swears revenge, which suggests that revenge and betrayal often go hand in hand.