Final answer:
The poem's romantic themes are showcased in natural and emotional imagery, while the gothic elements are seen in mysterious and supernatural details. The 'red-cross knight' symbolizes a Christian knight, reflecting chivalric traditions.
Step-by-step explanation:
The question pertains to romantic and gothic themes and imagery found in a poem. Romantic themes often deal with nature, beauty, and emotional experiences, whereas gothic themes might involve mysterious, dark, or supernatural elements. Traces of these can be seen through the descriptions of the natural world, heroic characters, and the aura of mystery surrounding the 'Lady of Shalott'. The term 'red-cross knight' refers to a knight bearing a red cross, symbolizing his allegiance to the Christian faith, commonly associated with the legendary Knights Templar. In the context of the poem, it describes a valiant figure faithful to his lady, reflective of chivalric romance.
'By good angels tenanted' is an example of gothic imagery, indicating a supernatural or divine presence within an idyllic setting. The romantic aspect is highlighted by the serene and beautiful landscape ('In the greenest of our valleys') and the notion of chivalry in the image of Sir Lancelot, a Knight of the Round Table, who is described with a sense of admiration for his shining armor that 'flamed upon the brazen greaves'. The passage describing Gil-Dong also incorporates gothic elements, with the old fellow attempting to unmask a young lady and Gil-Dong's attack on him, creating a dramatic and dark moment in the narrative.