Who is Dara from Beneath a Marble Sky: A Novel of the Taj Mahal and what is their importance?

Dara is Jahanara's beloved older brother. He is thoughtful and scholarly, spending his time translating ancient texts into readable languages, and composing treatises on religion. He does not have the stomach for warfare, however, and he leaves that arena to his brother, Aurangzeb, to his own peril.