In "The Eve of St. Agnes," how does John Keats connect the beadsman to the main story of the poem?
The poem is one of antitheses: for instance, cold/heat and waking/dreaming. The central antithesis, however, is Madeline's spiritual passion for all things holy developed in contrast to Porphyro's physical passion for Madeline. The beadsman contributes to specific parts of these antitheses.
As the poem begins, the beadsman prays alone in the chapel surrounded by religious imagery, including a picture of the Virgin. His presence introduces into the poem the element of spirituality. Furthermore, the chapel is incredibly cold, so cold that even the chapel's statues seem to feel it. The idea of the cold, then, is also introduced very early. As the poem develops, spirituality is soon contrasted with physical desire and cold is contrasted with the warmth of Madeline's chamber. Finally, at the poem's conclusion, the beadsman sleeps, dreaming his own holy dreams forever, after the lovers have run away together.