Oliver receives a visit from Charles, a wrestler who is in the employ of the Duke (beginning at line 83). Charles informs Oliver about the latest news in the court (and, hence, provides exposition – necessary background information – to Shakespeare’s audience). First, Charles repeats some old news that Frederick, the younger brother of Duke Senior (the old Duke), has usurped his place. Further, the new Duke (Frederick) has banished his older brother. Thus, a theme of sibling rivalry is one of the ways in which Shakespeare unites his two plots. The reader should note that Shakespeare subtly dispels any false beliefs about primogeniture and worthiness. In the plot involving the two dukes, the older brother is “good” and the younger brother is the “bad” one. But in the plot involving the two sons of Sir Rowland de Bois, the older brother is “bad” and the younger brother is “good.”
Duke Senior, as Charles relates, has taken refuge in the Forest of Ardenne; and several other lords loyal to Duke Senior have gone with him. The wily Duke Frederick immediately seized the property and money belonging to these lords; and, so, they too will never be allowed to return home.
Charles also tells Oliver (and the audience) about Rosalind, the daughter of Duke Senior. Charles explains that Rosalind is like a sister to Celia, the daughter of Duke Frederick. So, Rosalind is not banished but is instead treated like a daughter by the new Duke.