Lord Byron's poems "She walks in Beauty" and "Darkness" (vol. 2) are both in Tom Stoppard's Arcadia. Why do you think Stoppard chose to make Byron a central (though off-stage) character in his play, and what do these poems in particular contribute to his vision? (Look to the Romantic era in the Norton Anthology, vol. 2.)

Tom Stoppard's plays often focus on re-interpreting literary history and on using past literary characters or symbols in order to discover modern meanings. Of the two Byron poems cited, the first is the expression of what Byron was perhaps best known for during his lifetime: his amorous feelings and affairs. The second, "Darkness," is a grim dystopian depiction of the last days on earth after the sun and stars have been extinguished.
Stoppard's Arcadia juxtaposes the past (Byron's time, specifically the years 1809 to 1812) with the 1990s, when the play premiered. The personal conflicts of the characters are also juxtaposed with a meditation on scientific theories about heat reduction and the idea that the energy of the universe will eventually burn itself out. These dual aspects of the play can be seen, respectively, to be expressed in the two poems by Byron, while the figure of Byron is an unseen presence behind the action of the drama in both its past and present phases.
Stoppard's use of his poetry also emphasizes just how "modern" Byron really is. One often tends to think the Romantics had an idealized view of mankind and the world, and though this is true to an extent, much of their work was also dominated by a deep pessimism. Byron's work fits in especially well with a playwright such as Stoppard, whose dramas often focus on the absurdity and existential dilemmas of modern times.