The forest
Young Arthur is taken deep into the forest by Merlin and it is inside the forest where Arthur lives for a big portion of his life. While Arthur is inside the forest, nothing bad happens to him and he is exposed to virtually no type of harm at all. However, as soon as Arthur leaves the forest his problems begin once more. Because of this, we can claim that the forest is used here as a metaphor for safety.
Crossing the river
Towards the middle of the story, Arthur is forced to cross a dangerous river. After Arthur arrives on the other side, he learns for the first time the truth about who he is and about his purpose in life. The crossing of the river is thus used here as a metaphor for the act of finding one's true self.
The city
While Arthur lives inside the forest, the rest of the characters live inside the city, together with the King. Inside the city, a large number of unfortunate events take place on a daily basis. As such, we can claim that the city is used here as a metaphor for instability and danger.
Illness
Soon after Arthur becomes of age, the King falls ill and everyone is sure that he will die. The King does not give up his ideas even though it becomes clear that he will die. As such, we can claim that the illness is used here as a metaphor for moral depravity.
The sword
An important moment in the story is the one when Arthur finds the sword which once belonged to Merlin's father. This sword is a special one and is also linked with an important prophecy. As such, we can claim that the sword is used here as a metaphor for worthiness.
