Poe uses the word, “Porphyrogene” as a descriptor for this monarch. This made up adjective derives from the word “porhyrogentite,” referring to a “son born in line to the throne.” This is just another way of reconfirming that the monarch, “Thought,” is the rightful king of his domain.

What does Porphyrogene mean?

: a son born after the accession of his father to the throne : one born in the purple.

What is a winged odor?

A winged odor went away. The "ramparts" of a palace or a castle are the walls that surround and protect the building (like in the Star Spangled Banner: "O'er the ramparts we watched"). ... When the breezes pass along these walls, they come away smelling sweet (a "winged odor"). It's like a scratch-and-sniff palace.