In 1855-56, Randolph Rogers first conceived of The Somnambula as a partner piece to his popular statue Nydia. The Somnambula, or "the sleepwalker," relates to Somnus, the Roman god of sleep, but Rogers probably based this figure on Vincenzo Bellini's popular nineteenth-century opera La Sonnambula. The heroine of the opera, Amina, sleepwalks into the room of another man, whom she mistakes for her fiancé Elvino. In a jealous rage, Elvino accuses her of having a lover, who, to no avail, pleads with him that they are not in love, but that she is a "sleepwalker." Elvino realizes his mistake when Amina, lamp in her hand, sleepwalks across a bridge and almost falls, but is awakened and rescued.