Compare and contrast the characterization of the two fathers in Ivanhoe: Cedric and Isaac. Analyze how each is characterized, how they try to protect their children, and how they maintain their heritage.

Cedric is Ivanhoe's father, while Isaac is Rebecca's father. Both are men who are highly conscious of their respective heritages (Saxon and Jewish) and also highly flawed as individuals. Cedric is harder towards his son than Isaac is towards his daughter.
Cedric does not want to see Ivanhoe married to Lady Rowena, mainly because of his pride in his Saxon heritage. He cares more about the advancement of the Saxon people than he does about his son's own personal happiness. He would rather see Rowena in a more politically advantageous marriage that could help the Saxons. He also disinherits Ivanhoe when he goes off to fight for the Norman king, viewing this move as a betrayal of their Saxon heritage. This, more than anything else, shows how Cedric puts patriotism above his own son.
Isaac is presented as a stereotypical Jewish character, interested in profit more than much else. Unlike Cedric, he is presented as a timid man, since he lacks the same amount of social power as a member of an ethnic minority. However, he cares deeply about his daughter and would be willing to pay any price for her safety—even if he does struggle to give the money up. He is aware of how his heritage makes him an object of scorn in his society, but he tries to do the best he can to make a good living off people that despise him (yet still run to him to borrow money).

Cedric is characterized as an arrogant, violent person. He is angry at his son Ivanhoe for backing Richard (a Norman) as king. Cedric is also opposed to Ivanhoe's wish to marry Cedric's ward, Lady Rowena, who Cedric wants to marry to Lord Athelstane, a Saxon contender (or pretender, depending on your point of view) to the English throne. Cedric is not very protective of Ivanhoe. When Ivanhoe is wounded at the tournament, Cedric allows strangers to care for him. He also disinherits Ivanhoe for learning about Norman customs and ways.
Cedric wants very much to protect his threatened Saxon heritage and see a Saxon king on the English throne. He feels that his power has been diminished by the Normans, who he hates. Cedric puts his faith in his Saxon heritage, not realizing that the Saxons and Normans are too blended for England to go back to an idealized vision of Saxon purity. Cedric rejects Ivanhoe for accepting and adapting to that reality, and arguably cares for more for his fantasy of recapturing the past than for his living child.
In many ways, Isaac (Rebecca's Jewish father) is more of a father to Ivanhoe than his real father. He is the person who makes sure Ivanhoe has armor and a horse for the tournament. Isaac is a cautious man due to the prejudice against Jews, who are despised by both Normans and Saxons. As the narrator says:

there was no race existing on the earth, in the air, or the waters, who were the object of such an unremitting, general and relentless persecution as the Jews of this period.

Isaac nevertheless arranges for Ivanhoe to get medical care after he is wounded. This is provided by his daughter Rebecca, a skilled healer. Isaac, a kind hearted man, cares deeply about Rebecca and sends Ivanhoe to rescue her after she has been abducted. Thus, as a Jew, Isaac is a foil to Cedric. Hated by everyone, he doesn't participate in the hatred of a rival group, which is what drives Cedric as a character. This makes Isaac a more compassionate man.