Answer:
The noble castle represents the reward for those who have not been baptized. With this, Dante states that for him the value of an individual is not tied to religion but to his works.
Step-by-step explanation:
Before entering the first cycle of hell, Dante spots the place he calls the "noble castle." This castle is a peaceful and happy place, but it is not heaven. In it are the people who were not baptized, that is, the pagans, who lived before the coming of Jesus Christ to the earth, but had a right life; and children who died before being baptized.
As they were not baptized, they are pagans, and pagans cannot enter heaven. However, these people did good works while they were alive and unbaptized children have no sin, so it is not right to send them to hell. With this, Dante reveals that a person's worth is not related to religion, but to sinless life and the doing of good works.